Merge branch 'master' into docking (with fixes)

# Conflicts:
#	imgui.cpp
#	imgui_internal.h

.github/workflows/build.yml

@@ -168,7 +168,7 @@ jobs:
       run: make -C examples/example_sdl_opengl3
 
   MacOS:
-    runs-on: macOS-10.14
+    runs-on: macOS-latest
     steps:
     - uses: actions/checkout@v1
       with:
@@ -206,7 +206,7 @@ jobs:
       run: xcodebuild -project examples/example_apple_opengl2/example_apple_opengl2.xcodeproj -target example_osx_opengl2
 
   iOS:
-    runs-on: macOS-10.14
+    runs-on: macOS-latest
     steps:
     - uses: actions/checkout@v1
       with:

docs/CHANGELOG.txt

@@ -132,6 +132,8 @@ Other Changes:
   multi-line label and no frame padding, such as: multi-line text, small button, tree node item, etc.
   The second item was correctly offset to match text baseline, and would interact/display correctly,
   but it wouldn't push the contents area boundary low enough.
+- Scrollbar: Fixed an issue where scrollbars wouldn't display on the frame following a frame where
+  all child window contents would be culled.
 - ColorPicker: Fixed SV triangle gradient to block (broken in 1.73). (#2864, #2711). [@lewa-j]
 - TreeNode: Fixed combination of ImGuiTreeNodeFlags_SpanFullWidth and ImGuiTreeNodeFlags_OpenOnArrow
   incorrectly locating the arrow hit position to the left of the frame. (#2451, #2438, #1897)
@@ -141,8 +143,11 @@ Other Changes:
   interactions with custom multi-selections patterns. (#1896, #1861)
 - DragScalar, SliderScalar, InputScalar: Added p_ prefix to parameter that are pointers to the data
   to clarify how they are used, and more comments redirecting to the demo code. (#2844)
+- Error handling: Assert if user mistakenly calls End() instead of EndChild() on a child window. (#1651)
 - Misc: Optimized storage of window settings data (reducing allocation count).
 - Misc: Windows: Do not use _wfopen() if IMGUI_DISABLE_WIN32_FUNCTIONS is defined. (#2815)
+- Misc: Windows: Disabled win32 function by default when building with UWP. (#2892, #2895)
+- Misc: Using static_assert() when using C++11, instead of our own construct (avoid zealous Clang warnings).
 - Docs: Improved and moved FAQ to docs/FAQ.md so it can be readable on the web. [@ButternCream, @ocornut]
 - Docs: Added permanent redirect from https://www.dearimgui.org/faq to FAQ page.
 - Demo: Added simple item reordering demo in Widgets -> Drag and Drop section. (#2823, #143) [@rokups]

imgui.cpp

@@ -54,6 +54,7 @@ CODE
 // [SECTION] ImGuiListClipper
 // [SECTION] RENDER HELPERS
 // [SECTION] MAIN CODE (most of the code! lots of stuff, needs tidying up!)
+// [SECTION] ERROR CHECKING
 // [SECTION] SCROLLING
 // [SECTION] TOOLTIPS
 // [SECTION] POPUPS
@@ -362,7 +363,7 @@ CODE
  - 2019/XX/XX (1.XX) - Moved IME support functions from io.ImeSetInputScreenPosFn, io.ImeWindowHandle to the PlatformIO api.
 
 
- - 2019/10/22 (1.74) - removed redirecting functions/enums that were marked obsolete in 1.52 (October 2017): Begin() (5 arguments signature), IsRootWindowOrAnyChildHovered(), AlignFirstTextHeightToWidgets(), SetNextWindowPosCenter(), ImFont::Glyph. Grep this log for details and new names, or see how they were implemented until 1.73.
+ - 2019/10/22 (1.74) - removed redirecting functions/enums that were marked obsolete in 1.52 (October 2017): Begin() (5 arguments signature), IsRootWindowOrAnyChildHovered(), AlignFirstTextHeightToWidgets(), SetNextWindowPosCenter(), ImFont::Glyph. See docs/Changelog.txt or grep this log for details and new names, or see how they were implemented until 1.73.
  - 2019/10/14 (1.74) - inputs: Fixed a miscalculation in the keyboard/mouse "typematic" repeat delay/rate calculation, used by keys and e.g. repeating mouse buttons as well as the GetKeyPressedAmount() function.
                        if you were using a non-default value for io.KeyRepeatRate (previous default was 0.250), you can add +io.KeyRepeatDelay to it to compensate for the fix.
                        The function was triggering on: 0.0 and (delay+rate*N) where (N>=1). Fixed formula responds to (N>=0). Effectively it made io.KeyRepeatRate behave like it was set to (io.KeyRepeatRate + io.KeyRepeatDelay).
@@ -853,7 +854,6 @@ static void             SetCurrentWindow(ImGuiWindow* window);
 static void             SetWindowHitTestHole(ImGuiWindow* window, const ImVec2& pos, const ImVec2& size);
 static void             FindHoveredWindow();
 static ImGuiWindow*     CreateNewWindow(const char* name, ImVec2 size, ImGuiWindowFlags flags);
-static void             CheckStacksSize(ImGuiWindow* window, bool write);
 static ImVec2           CalcNextScrollFromScrollTargetAndClamp(ImGuiWindow* window, bool snap_on_edges);
 
 static void             AddDrawListToDrawData(ImVector<ImDrawList*>* out_list, ImDrawList* draw_list);
@@ -886,6 +886,10 @@ static void             NavSaveLastChildNavWindowIntoParent(ImGuiWindow* nav_win
 static ImGuiWindow*     NavRestoreLastChildNavWindow(ImGuiWindow* window);
 static int              FindWindowFocusIndex(ImGuiWindow* window);
 
+// Error Checking
+static void             ErrorCheckEndFrame();
+static void             ErrorCheckBeginEndCompareStacksSize(ImGuiWindow* window, bool write);
+
 // Misc
 static void             UpdateMouseInputs();
 static void             UpdateMouseWheel();
@@ -3748,7 +3752,7 @@ void ImGui::NewFrame()
     }
 
     g.Time += g.IO.DeltaTime;
-    g.FrameScopeActive = true;
+    g.WithinFrameScope = true;
     g.FrameCount += 1;
     g.TooltipOverrideCount = 0;
     g.WindowsActiveCount = 0;
@@ -3931,7 +3935,7 @@ void ImGui::NewFrame()
     // Create implicit/fallback window - which we will only render it if the user has added something to it.
     // We don't use "Debug" to avoid colliding with user trying to create a "Debug" window with custom flags.
     // This fallback is particularly important as it avoid ImGui:: calls from crashing.
-    g.FrameScopePushedFallbackWindow = true;
+    g.WithinFrameScopeWithImplicitWindow = true;
     SetNextWindowSize(ImVec2(400,400), ImGuiCond_FirstUseEver);
     Begin("Debug##Default");
     IM_ASSERT(g.CurrentWindow->IsFallbackWindow == true);
@@ -4285,7 +4289,7 @@ void ImGui::EndFrame()
     IM_ASSERT(g.Initialized);
     if (g.FrameCountEnded == g.FrameCount)          // Don't process EndFrame() multiple times.
         return;
-    IM_ASSERT(g.FrameScopeActive && "Forgot to call ImGui::NewFrame()?");
+    IM_ASSERT(g.WithinFrameScope && "Forgot to call ImGui::NewFrame()?");
 
     // Notify OS when our Input Method Editor cursor has moved (e.g. CJK inputs using Microsoft IME)
     if (g.PlatformIO.Platform_SetImeInputPos && (g.PlatformImeLastPos.x == FLT_MAX || ImLengthSqr(g.PlatformImePos - g.PlatformImeLastPos) > 0.0001f))
@@ -4296,24 +4300,10 @@ void ImGui::EndFrame()
             g.PlatformImePosViewport = NULL;
         }
 
-    // Report when there is a mismatch of Begin/BeginChild vs End/EndChild calls. Important: Remember that the Begin/BeginChild API requires you
+    ErrorCheckEndFrame();
-    // to always call End/EndChild even if Begin/BeginChild returns false! (this is unfortunately inconsistent with most other Begin* API).
-    if (g.CurrentWindowStack.Size != 1)
-    {
-        if (g.CurrentWindowStack.Size > 1)
-        {
-            IM_ASSERT(g.CurrentWindowStack.Size == 1 && "Mismatched Begin/BeginChild vs End/EndChild calls: did you forget to call End/EndChild?");
-            while (g.CurrentWindowStack.Size > 1) // FIXME-ERRORHANDLING
-                End();
-        }
-        else
-        {
-            IM_ASSERT(g.CurrentWindowStack.Size == 1 && "Mismatched Begin/BeginChild vs End/EndChild calls: did you call End/EndChild too much?");
-        }
-    }
 
     // Hide implicit/fallback "Debug" window if it hasn't been used
-    g.FrameScopePushedFallbackWindow = false;
+    g.WithinFrameScopeWithImplicitWindow = false;
     if (g.CurrentWindow && !g.CurrentWindow->WriteAccessed)
         g.CurrentWindow->Active = false;
     End();
@@ -4345,7 +4335,7 @@ void ImGui::EndFrame()
     }
 
     // End frame
-    g.FrameScopeActive = false;
+    g.WithinFrameScope = false;
     g.FrameCountEnded = g.FrameCount;
 
     // Initiate moving window + handle left-click and right-click focus
@@ -4959,7 +4949,10 @@ void ImGui::EndChild()
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
 
+    IM_ASSERT(g.WithinEndChild == false);
     IM_ASSERT(window->Flags & ImGuiWindowFlags_ChildWindow);   // Mismatched BeginChild()/EndChild() callss
+
+    g.WithinEndChild = true;
     if (window->BeginCount > 1)
     {
         End();
@@ -4991,6 +4984,7 @@ void ImGui::EndChild()
             ItemAdd(bb, 0);
         }
     }
+    g.WithinEndChild = false;
 }
 
 // Helper to create a child window / scrolling region that looks like a normal widget frame.
@@ -5013,22 +5007,6 @@ void ImGui::EndChildFrame()
     EndChild();
 }
 
-// Save and compare stack sizes on Begin()/End() to detect usage errors
-static void CheckStacksSize(ImGuiWindow* window, bool write)
-{
-    // NOT checking: DC.ItemWidth, DC.AllowKeyboardFocus, DC.ButtonRepeat, DC.TextWrapPos (per window) to allow user to conveniently push once and not pop (they are cleared on Begin)
-    ImGuiContext& g = *GImGui;
-    short* p_backup = &window->DC.StackSizesBackup[0];
-    { int current = window->IDStack.Size;       if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup == current && "PushID/PopID or TreeNode/TreePop Mismatch!");   p_backup++; }    // Too few or too many PopID()/TreePop()
-    { int current = window->DC.GroupStack.Size; if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup == current && "BeginGroup/EndGroup Mismatch!");                p_backup++; }    // Too few or too many EndGroup()
-    { int current = g.BeginPopupStack.Size;     if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup == current && "BeginMenu/EndMenu or BeginPopup/EndPopup Mismatch"); p_backup++;}// Too few or too many EndMenu()/EndPopup()
-    // For color, style and font stacks there is an incentive to use Push/Begin/Pop/.../End patterns, so we relax our checks a little to allow them.
-    { int current = g.ColorModifiers.Size;      if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup >= current && "PushStyleColor/PopStyleColor Mismatch!");       p_backup++; }    // Too few or too many PopStyleColor()
-    { int current = g.StyleModifiers.Size;      if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup >= current && "PushStyleVar/PopStyleVar Mismatch!");           p_backup++; }    // Too few or too many PopStyleVar()
-    { int current = g.FontStack.Size;           if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup >= current && "PushFont/PopFont Mismatch!");                   p_backup++; }    // Too few or too many PopFont()
-    IM_ASSERT(p_backup == window->DC.StackSizesBackup + IM_ARRAYSIZE(window->DC.StackSizesBackup));
-}
-
 static void SetWindowConditionAllowFlags(ImGuiWindow* window, ImGuiCond flags, bool enabled)
 {
     window->SetWindowPosAllowFlags       = enabled ? (window->SetWindowPosAllowFlags       | flags) : (window->SetWindowPosAllowFlags       & ~flags);
@@ -5455,6 +5433,9 @@ void ImGui::RenderWindowDecorations(ImGuiWindow* window, const ImRect& title_bar
     ImGuiStyle& style = g.Style;
     ImGuiWindowFlags flags = window->Flags;
 
+    // Ensure that ScrollBar doesn't read last frame's SkipItems
+    window->SkipItems = false;
+
     // Draw window + handle manual resize
     // As we highlight the title bar when want_focus is set, multiple reappearing windows will have have their title bar highlighted on their reappearing frame.
     const float window_rounding = window->WindowRounding;
@@ -5677,7 +5658,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
     ImGuiContext& g = *GImGui;
     const ImGuiStyle& style = g.Style;
     IM_ASSERT(name != NULL && name[0] != '\0');     // Window name required
-    IM_ASSERT(g.FrameScopeActive);                  // Forgot to call ImGui::NewFrame()
+    IM_ASSERT(g.WithinFrameScope);                  // Forgot to call ImGui::NewFrame()
     IM_ASSERT(g.FrameCountEnded != g.FrameCount);   // Called ImGui::Render() or ImGui::EndFrame() and haven't called ImGui::NewFrame() again yet
 
     // Find or create
@@ -5698,7 +5679,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
 
     const int current_frame = g.FrameCount;
     const bool first_begin_of_the_frame = (window->LastFrameActive != current_frame);
-    window->IsFallbackWindow = (g.CurrentWindowStack.Size == 0 && g.FrameScopePushedFallbackWindow);
+    window->IsFallbackWindow = (g.CurrentWindowStack.Size == 0 && g.WithinFrameScopeWithImplicitWindow);
 
     // Update the Appearing flag
     bool window_just_activated_by_user = (window->LastFrameActive < current_frame - 1);   // Not using !WasActive because the implicit "Debug" window would always toggle off->on
@@ -5760,7 +5741,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
     // We intentionally set g.CurrentWindow to NULL to prevent usage until when the viewport is set, then will call SetCurrentWindow()
     g.CurrentWindowStack.push_back(window);
     g.CurrentWindow = NULL;
-    CheckStacksSize(window, true);
+    ErrorCheckBeginEndCompareStacksSize(window, true);
     if (flags & ImGuiWindowFlags_Popup)
     {
         ImGuiPopupData& popup_ref = g.OpenPopupStack[g.BeginPopupStack.Size];
@@ -6484,16 +6465,21 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
 void ImGui::End()
 {
     ImGuiContext& g = *GImGui;
+    ImGuiWindow* window = g.CurrentWindow;
 
-    if (g.CurrentWindowStack.Size <= 1 && g.FrameScopePushedFallbackWindow)
+    // Error checking: verify that user hasn't called End() too many times!
+    if (g.CurrentWindowStack.Size <= 1 && g.WithinFrameScopeWithImplicitWindow)
     {
-        IM_ASSERT(g.CurrentWindowStack.Size > 1 && "Calling End() too many times!");
+        IMGUI_USER_ERROR(g.CurrentWindowStack.Size > 1, "Calling End() too many times!");
-        return; // FIXME-ERRORHANDLING
+        return;
     }
     IM_ASSERT(g.CurrentWindowStack.Size > 0);
 
-    ImGuiWindow* window = g.CurrentWindow;
+    // Error checking: verify that user doesn't directly call End() on a child window.
+    if ((window->Flags & ImGuiWindowFlags_ChildWindow) && !window->DockIsActive)
+        IMGUI_USER_ERROR(g.WithinEndChild, "Must call EndChild() and not End()!");
 
+    // Close anything that is open
     if (window->DC.CurrentColumns)
         EndColumns();
     if (!(window->Flags & ImGuiWindowFlags_DockNodeHost))   // Pop inner window clip rectangle
@@ -6512,7 +6498,7 @@ void ImGui::End()
     g.CurrentWindowStack.pop_back();
     if (window->Flags & ImGuiWindowFlags_Popup)
         g.BeginPopupStack.pop_back();
-    CheckStacksSize(window, false);
+    ErrorCheckBeginEndCompareStacksSize(window, false);
     SetCurrentWindow(g.CurrentWindowStack.empty() ? NULL : g.CurrentWindowStack.back());
     if (g.CurrentWindow)
         SetCurrentViewport(g.CurrentWindow, g.CurrentWindow->Viewport);
@@ -7727,6 +7713,54 @@ void ImGui::Unindent(float indent_w)
 }
 
 
+//-----------------------------------------------------------------------------
+// [SECTION] ERROR CHECKING
+//-----------------------------------------------------------------------------
+
+static void ImGui::ErrorCheckEndFrame()
+{
+    // Report when there is a mismatch of Begin/BeginChild vs End/EndChild calls. Important: Remember that the Begin/BeginChild API requires you
+    // to always call End/EndChild even if Begin/BeginChild returns false! (this is unfortunately inconsistent with most other Begin* API).
+    ImGuiContext& g = *GImGui;
+    if (g.CurrentWindowStack.Size != 1)
+    {
+        if (g.CurrentWindowStack.Size > 1)
+        {
+            IMGUI_USER_ERROR(g.CurrentWindowStack.Size == 1, "Mismatched Begin/BeginChild vs End/EndChild calls: did you forget to call End/EndChild?");
+            while (g.CurrentWindowStack.Size > 1)
+                End();
+        }
+        else
+        {
+            IMGUI_USER_ERROR(g.CurrentWindowStack.Size == 1, "Mismatched Begin/BeginChild vs End/EndChild calls: did you call End/EndChild too much?");
+        }
+    }
+
+}
+
+// Save and compare stack sizes on Begin()/End() to detect usage errors
+// Begin() calls this with write=true
+// End() calls this with write=false
+static void ImGui::ErrorCheckBeginEndCompareStacksSize(ImGuiWindow* window, bool write)
+{
+    ImGuiContext& g = *GImGui;
+    short* p = &window->DC.StackSizesBackup[0];
+
+    // Window stacks
+    // NOT checking: DC.ItemWidth, DC.AllowKeyboardFocus, DC.ButtonRepeat, DC.TextWrapPos (per window) to allow user to conveniently push once and not pop (they are cleared on Begin)
+    { int n = window->IDStack.Size;       if (write) *p = (short)n; else IM_ASSERT(*p == n && "PushID/PopID or TreeNode/TreePop Mismatch!");   p++; }    // Too few or too many PopID()/TreePop()
+    { int n = window->DC.GroupStack.Size; if (write) *p = (short)n; else IM_ASSERT(*p == n && "BeginGroup/EndGroup Mismatch!");                p++; }    // Too few or too many EndGroup()
+
+    // Global stacks
+    // For color, style and font stacks there is an incentive to use Push/Begin/Pop/.../End patterns, so we relax our checks a little to allow them.
+    { int n = g.BeginPopupStack.Size;     if (write) *p = (short)n; else IM_ASSERT(*p == n && "BeginMenu/EndMenu or BeginPopup/EndPopup Mismatch!"); p++; }// Too few or too many EndMenu()/EndPopup()
+    { int n = g.ColorModifiers.Size;      if (write) *p = (short)n; else IM_ASSERT(*p >= n && "PushStyleColor/PopStyleColor Mismatch!");       p++; }    // Too few or too many PopStyleColor()
+    { int n = g.StyleModifiers.Size;      if (write) *p = (short)n; else IM_ASSERT(*p >= n && "PushStyleVar/PopStyleVar Mismatch!");           p++; }    // Too few or too many PopStyleVar()
+    { int n = g.FontStack.Size;           if (write) *p = (short)n; else IM_ASSERT(*p >= n && "PushFont/PopFont Mismatch!");                   p++; }    // Too few or too many PopFont()
+    IM_ASSERT(p == window->DC.StackSizesBackup + IM_ARRAYSIZE(window->DC.StackSizesBackup));
+}
+
+
 //-----------------------------------------------------------------------------
 // [SECTION] SCROLLING
 //-----------------------------------------------------------------------------
@@ -8209,13 +8243,19 @@ bool ImGui::BeginPopupModal(const char* name, bool* p_open, ImGuiWindowFlags fla
 void ImGui::EndPopup()
 {
     ImGuiContext& g = *GImGui;
-    IM_ASSERT(g.CurrentWindow->Flags & ImGuiWindowFlags_Popup);  // Mismatched BeginPopup()/EndPopup() calls
+    ImGuiWindow* window = g.CurrentWindow;
+    IM_ASSERT(window->Flags & ImGuiWindowFlags_Popup);  // Mismatched BeginPopup()/EndPopup() calls
     IM_ASSERT(g.BeginPopupStack.Size > 0);
 
     // Make all menus and popups wrap around for now, may need to expose that policy.
-    NavMoveRequestTryWrapping(g.CurrentWindow, ImGuiNavMoveFlags_LoopY);
+    NavMoveRequestTryWrapping(window, ImGuiNavMoveFlags_LoopY);
 
+    // Child-popups don't need to be layed out
+    IM_ASSERT(g.WithinEndChild == false);
+    if (window->Flags & ImGuiWindowFlags_ChildWindow)
+        g.WithinEndChild = true;
     End();
+    g.WithinEndChild = false;
 }
 
 bool ImGui::OpenPopupOnItemClick(const char* str_id, int mouse_button)
@@ -8913,7 +8953,7 @@ static void ImGui::NavUpdate()
     g.IO.NavVisible = (g.IO.NavActive && g.NavId != 0 && !g.NavDisableHighlight) || (g.NavWindowingTarget != NULL);
 
     // Process NavCancel input (to close a popup, get back to parent, clear focus)
-    if (IsNavInputPressed(ImGuiNavInput_Cancel, ImGuiInputReadMode_Pressed))
+    if (IsNavInputTest(ImGuiNavInput_Cancel, ImGuiInputReadMode_Pressed))
     {
         if (g.ActiveId != 0)
         {
@@ -8957,14 +8997,14 @@ static void ImGui::NavUpdate()
     if (g.NavId != 0 && !g.NavDisableHighlight && !g.NavWindowingTarget && g.NavWindow && !(g.NavWindow->Flags & ImGuiWindowFlags_NoNavInputs))
     {
         bool activate_down = IsNavInputDown(ImGuiNavInput_Activate);
-        bool activate_pressed = activate_down && IsNavInputPressed(ImGuiNavInput_Activate, ImGuiInputReadMode_Pressed);
+        bool activate_pressed = activate_down && IsNavInputTest(ImGuiNavInput_Activate, ImGuiInputReadMode_Pressed);
         if (g.ActiveId == 0 && activate_pressed)
             g.NavActivateId = g.NavId;
         if ((g.ActiveId == 0 || g.ActiveId == g.NavId) && activate_down)
             g.NavActivateDownId = g.NavId;
         if ((g.ActiveId == 0 || g.ActiveId == g.NavId) && activate_pressed)
             g.NavActivatePressedId = g.NavId;
-        if ((g.ActiveId == 0 || g.ActiveId == g.NavId) && IsNavInputPressed(ImGuiNavInput_Input, ImGuiInputReadMode_Pressed))
+        if ((g.ActiveId == 0 || g.ActiveId == g.NavId) && IsNavInputTest(ImGuiNavInput_Input, ImGuiInputReadMode_Pressed))
             g.NavInputId = g.NavId;
     }
     if (g.NavWindow && (g.NavWindow->Flags & ImGuiWindowFlags_NoNavInputs))
@@ -8985,10 +9025,11 @@ static void ImGui::NavUpdate()
         g.NavMoveRequestFlags = ImGuiNavMoveFlags_None;
         if (g.NavWindow && !g.NavWindowingTarget && !(g.NavWindow->Flags & ImGuiWindowFlags_NoNavInputs))
         {
-            if (!IsActiveIdUsingNavDir(ImGuiDir_Left)    && IsNavInputPressedAnyOfTwo(ImGuiNavInput_DpadLeft, ImGuiNavInput_KeyLeft_, ImGuiInputReadMode_Repeat)) { g.NavMoveDir = ImGuiDir_Left; }
+            const ImGuiInputReadMode read_mode = ImGuiInputReadMode_Repeat;
-            if (!IsActiveIdUsingNavDir(ImGuiDir_Right)   && IsNavInputPressedAnyOfTwo(ImGuiNavInput_DpadRight,ImGuiNavInput_KeyRight_,ImGuiInputReadMode_Repeat)) { g.NavMoveDir = ImGuiDir_Right; }
+            if (!IsActiveIdUsingNavDir(ImGuiDir_Left)  && (IsNavInputTest(ImGuiNavInput_DpadLeft,  read_mode) || IsNavInputTest(ImGuiNavInput_KeyLeft_,  read_mode))) { g.NavMoveDir = ImGuiDir_Left; }
-            if (!IsActiveIdUsingNavDir(ImGuiDir_Up)      && IsNavInputPressedAnyOfTwo(ImGuiNavInput_DpadUp,   ImGuiNavInput_KeyUp_,   ImGuiInputReadMode_Repeat)) { g.NavMoveDir = ImGuiDir_Up; }
+            if (!IsActiveIdUsingNavDir(ImGuiDir_Right) && (IsNavInputTest(ImGuiNavInput_DpadRight, read_mode) || IsNavInputTest(ImGuiNavInput_KeyRight_, read_mode))) { g.NavMoveDir = ImGuiDir_Right; }
-            if (!IsActiveIdUsingNavDir(ImGuiDir_Down)    && IsNavInputPressedAnyOfTwo(ImGuiNavInput_DpadDown, ImGuiNavInput_KeyDown_, ImGuiInputReadMode_Repeat)) { g.NavMoveDir = ImGuiDir_Down; }
+            if (!IsActiveIdUsingNavDir(ImGuiDir_Up)    && (IsNavInputTest(ImGuiNavInput_DpadUp,    read_mode) || IsNavInputTest(ImGuiNavInput_KeyUp_,    read_mode))) { g.NavMoveDir = ImGuiDir_Up; }
+            if (!IsActiveIdUsingNavDir(ImGuiDir_Down)  && (IsNavInputTest(ImGuiNavInput_DpadDown,  read_mode) || IsNavInputTest(ImGuiNavInput_KeyDown_,  read_mode))) { g.NavMoveDir = ImGuiDir_Down; }
         }
         g.NavMoveClipDir = g.NavMoveDir;
     }
@@ -9283,7 +9324,7 @@ static void ImGui::NavUpdateWindowing()
     }
 
     // Start CTRL-TAB or Square+L/R window selection
-    bool start_windowing_with_gamepad = !g.NavWindowingTarget && IsNavInputPressed(ImGuiNavInput_Menu, ImGuiInputReadMode_Pressed);
+    bool start_windowing_with_gamepad = !g.NavWindowingTarget && IsNavInputTest(ImGuiNavInput_Menu, ImGuiInputReadMode_Pressed);
     bool start_windowing_with_keyboard = !g.NavWindowingTarget && g.IO.KeyCtrl && IsKeyPressedMap(ImGuiKey_Tab) && (g.IO.ConfigFlags & ImGuiConfigFlags_NavEnableKeyboard);
     if (start_windowing_with_gamepad || start_windowing_with_keyboard)
         if (ImGuiWindow* window = g.NavWindow ? g.NavWindow : FindWindowNavFocusable(g.WindowsFocusOrder.Size - 1, -INT_MAX, -1))
@@ -9302,7 +9343,7 @@ static void ImGui::NavUpdateWindowing()
         g.NavWindowingHighlightAlpha = ImMax(g.NavWindowingHighlightAlpha, ImSaturate((g.NavWindowingTimer - NAV_WINDOWING_HIGHLIGHT_DELAY) / 0.05f));
 
         // Select window to focus
-        const int focus_change_dir = (int)IsNavInputPressed(ImGuiNavInput_FocusPrev, ImGuiInputReadMode_RepeatSlow) - (int)IsNavInputPressed(ImGuiNavInput_FocusNext, ImGuiInputReadMode_RepeatSlow);
+        const int focus_change_dir = (int)IsNavInputTest(ImGuiNavInput_FocusPrev, ImGuiInputReadMode_RepeatSlow) - (int)IsNavInputTest(ImGuiNavInput_FocusNext, ImGuiInputReadMode_RepeatSlow);
         if (focus_change_dir != 0)
         {
             NavUpdateWindowingHighlightWindow(focus_change_dir);
@@ -9334,9 +9375,9 @@ static void ImGui::NavUpdateWindowing()
 
     // Keyboard: Press and Release ALT to toggle menu layer
     // FIXME: We lack an explicit IO variable for "is the imgui window focused", so compare mouse validity to detect the common case of back-end clearing releases all keys on ALT-TAB
-    if (IsNavInputPressed(ImGuiNavInput_KeyMenu_, ImGuiInputReadMode_Pressed))
+    if (IsNavInputTest(ImGuiNavInput_KeyMenu_, ImGuiInputReadMode_Pressed))
         g.NavWindowingToggleLayer = true;
-    if ((g.ActiveId == 0 || g.ActiveIdAllowOverlap) && g.NavWindowingToggleLayer && IsNavInputPressed(ImGuiNavInput_KeyMenu_, ImGuiInputReadMode_Released))
+    if ((g.ActiveId == 0 || g.ActiveIdAllowOverlap) && g.NavWindowingToggleLayer && IsNavInputTest(ImGuiNavInput_KeyMenu_, ImGuiInputReadMode_Released))
         if (IsMousePosValid(&g.IO.MousePos) == IsMousePosValid(&g.IO.MousePosPrev))
             apply_toggle_layer = true;
 
@@ -13559,7 +13600,9 @@ void ImGui::DockSpace(ImGuiID id, const ImVec2& size_arg, ImGuiDockNodeFlags fla
     IM_ASSERT(node->IsRootNode());
     DockNodeUpdate(node);
 
+    g.WithinEndChild = true;
     End();
+    g.WithinEndChild = false;
 }
 
 // Tips: Use with ImGuiDockNodeFlags_PassthruCentralNode!
@@ -14484,6 +14527,10 @@ static void ImGui::DockSettingsHandler_WriteAll(ImGuiContext* ctx, ImGuiSettings
 #else
 #include <windows.h>
 #endif
+#if defined(WINAPI_FAMILY) && (WINAPI_FAMILY == WINAPI_FAMILY_APP) // UWP doesn't have Win32 functions
+#define IMGUI_DISABLE_WIN32_DEFAULT_CLIPBOARD_FUNCTIONS
+#define IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCTIONS
+#endif
 #elif defined(__APPLE__)
 #include <TargetConditionals.h>
 #endif
@@ -14676,6 +14723,21 @@ void ImGui::ShowViewportThumbnails()
 }
 
 #ifndef IMGUI_DISABLE_METRICS_WINDOW
+
+// Avoid naming collision with imgui_demo.cpp's HelpMarker() for unity builds.
+static void MetricsHelpMarker(const char* desc)
+{
+    ImGui::TextDisabled("(?)");
+    if (ImGui::IsItemHovered())
+    {
+        ImGui::BeginTooltip();
+        ImGui::PushTextWrapPos(ImGui::GetFontSize() * 35.0f);
+        ImGui::TextUnformatted(desc);
+        ImGui::PopTextWrapPos();
+        ImGui::EndTooltip();
+    }
+}
+
 void ImGui::ShowMetricsWindow(bool* p_open)
 {
     if (!ImGui::Begin("Dear ImGui Metrics", p_open))
@@ -14820,7 +14882,10 @@ void ImGui::ShowMetricsWindow(bool* p_open)
                 ImGui::BulletText("%s: NULL", label);
                 return;
             }
-            if (!ImGui::TreeNode(window, "%s '%s', %d @ 0x%p", label, window->Name, (window->Active || window->WasActive), window))
+            bool open = ImGui::TreeNode(window, "%s '%s', %d @ 0x%p", label, window->Name, (window->Active || window->WasActive), window);
+            if (ImGui::IsItemHovered() && window->WasActive)
+                ImGui::GetForegroundDrawList()->AddRect(window->Pos, window->Pos + window->Size, IM_COL32(255, 255, 0, 255));
+            if (!open)
                 return;
             ImGuiWindowFlags flags = window->Flags;
             NodeDrawList(window, window->Viewport, window->DrawList, "DrawList");
@@ -14830,7 +14895,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
                 (flags & ImGuiWindowFlags_Modal)        ? "Modal " : "",      (flags & ImGuiWindowFlags_ChildMenu)   ? "ChildMenu " : "",  (flags & ImGuiWindowFlags_NoSavedSettings) ? "NoSavedSettings " : "",
                 (flags & ImGuiWindowFlags_NoMouseInputs)? "NoMouseInputs":"", (flags & ImGuiWindowFlags_NoNavInputs) ? "NoNavInputs" : "", (flags & ImGuiWindowFlags_AlwaysAutoResize) ? "AlwaysAutoResize" : "");
             ImGui::BulletText("WindowClassId: 0x%08X", window->WindowClass.ClassId);
-            ImGui::BulletText("Scroll: (%.2f/%.2f,%.2f/%.2f)", window->Scroll.x, window->ScrollMax.x, window->Scroll.y, window->ScrollMax.y);
+            ImGui::BulletText("Scroll: (%.2f/%.2f,%.2f/%.2f) Scrollbar:%s%s", window->Scroll.x, window->ScrollMax.x, window->Scroll.y, window->ScrollMax.y, window->ScrollbarX ? "X" : "", window->ScrollbarY ? "Y" : "");
             ImGui::BulletText("Active: %d/%d, WriteAccessed: %d, BeginOrderWithinContext: %d", window->Active, window->WasActive, window->WriteAccessed, (window->Active || window->WasActive) ? window->BeginOrderWithinContext : -1);
             ImGui::BulletText("Appearing: %d, Hidden: %d (CanSkip %d Cannot %d), SkipItems: %d", window->Appearing, window->Hidden, window->HiddenFramesCanSkipItems, window->HiddenFramesCannotSkipItems, window->SkipItems);
             ImGui::BulletText("NavLastIds: 0x%08X,0x%08X, NavLayerActiveMask: %X", window->NavLastIds[0], window->NavLastIds[1], window->DC.NavLayerActiveMask);
@@ -15096,6 +15161,8 @@ void ImGui::ShowMetricsWindow(bool* p_open)
         // The Item Picker tool is super useful to visually select an item and break into the call-stack of where it was submitted.
         if (ImGui::Button("Item Picker.."))
             ImGui::DebugStartItemPicker();
+        ImGui::SameLine();
+        MetricsHelpMarker("Will call the IM_DEBUG_BREAK() macro to break in debugger.\nWarning: If you don't have a debugger attached, this will probably crash.");
 
         ImGui::Checkbox("Show windows begin order", &show_windows_begin_order);
         ImGui::Checkbox("Show windows rectangles", &show_windows_rects);

imgui_demo.cpp

@@ -2273,7 +2273,7 @@ static void ShowDemoWindowLayout()
             ImGui::TextUnformatted(names[i]);
 
             ImGuiWindowFlags child_flags = enable_extra_decorations ? ImGuiWindowFlags_MenuBar : 0;
-            ImGui::BeginChild(ImGui::GetID((void*)(intptr_t)i), ImVec2(child_w, 200.0f), true, child_flags);
+            bool window_visible = ImGui::BeginChild(ImGui::GetID((void*)(intptr_t)i), ImVec2(child_w, 200.0f), true, child_flags);
             if (ImGui::BeginMenuBar())
             {
                 ImGui::TextUnformatted("abc");
@@ -2283,11 +2283,13 @@ static void ShowDemoWindowLayout()
                 ImGui::SetScrollY(scroll_to_off_px);
             if (scroll_to_pos)
                 ImGui::SetScrollFromPosY(ImGui::GetCursorStartPos().y + scroll_to_pos_px, i * 0.25f);
+            if (window_visible) // Avoid calling SetScrollHereY when running with culled items
+            {
                 for (int item = 0; item < 100; item++)
                 {
                     if (enable_track && item == track_item)
                     {
-                    ImGui::TextColored(ImVec4(1,1,0,1), "Item %d", item);
+                        ImGui::TextColored(ImVec4(1, 1, 0, 1), "Item %d", item);
                         ImGui::SetScrollHereY(i * 0.25f); // 0.0f:top, 0.5f:center, 1.0f:bottom
                     }
                     else
@@ -2295,6 +2297,7 @@ static void ShowDemoWindowLayout()
                         ImGui::Text("Item %d", item);
                     }
                 }
+            }
             float scroll_y = ImGui::GetScrollY();
             float scroll_max_y = ImGui::GetScrollMaxY();
             ImGui::EndChild();
@@ -2311,11 +2314,13 @@ static void ShowDemoWindowLayout()
         {
             float child_height = ImGui::GetTextLineHeight() + style.ScrollbarSize + style.WindowPadding.y * 2.0f;
             ImGuiWindowFlags child_flags = ImGuiWindowFlags_HorizontalScrollbar | (enable_extra_decorations ? ImGuiWindowFlags_AlwaysVerticalScrollbar : 0);
-            ImGui::BeginChild(ImGui::GetID((void*)(intptr_t)i), ImVec2(-100, child_height), true, child_flags);
+            bool window_visible = ImGui::BeginChild(ImGui::GetID((void*)(intptr_t)i), ImVec2(-100, child_height), true, child_flags);
             if (scroll_to_off)
                 ImGui::SetScrollX(scroll_to_off_px);
             if (scroll_to_pos)
                 ImGui::SetScrollFromPosX(ImGui::GetCursorStartPos().x + scroll_to_pos_px, i * 0.25f);
+            if (window_visible) // Avoid calling SetScrollHereY when running with culled items
+            {
                 for (int item = 0; item < 100; item++)
                 {
                     if (enable_track && item == track_item)
@@ -2329,6 +2334,7 @@ static void ShowDemoWindowLayout()
                     }
                     ImGui::SameLine();
                 }
+            }
             float scroll_x = ImGui::GetScrollX();
             float scroll_max_x = ImGui::GetScrollMaxX();
             ImGui::EndChild();

imgui_internal.h

@@ -162,12 +162,21 @@ extern IMGUI_API ImGuiContext* GImGui;  // Current implicit context pointer
 #define IM_NEWLINE      "\n"
 #endif
 #define IM_TABSIZE      (4)
+#if (__cplusplus >= 201100)
+#define IM_STATIC_ASSERT(_COND)         static_assert(_COND, "")
+#else
 #define IM_STATIC_ASSERT(_COND)         typedef char static_assertion_##__line__[(_COND)?1:-1]
+#endif
 #define IM_F32_TO_INT8_UNBOUND(_VAL)    ((int)((_VAL) * 255.0f + ((_VAL)>=0 ? 0.5f : -0.5f)))   // Unsaturated, for display purpose
 #define IM_F32_TO_INT8_SAT(_VAL)        ((int)(ImSaturate(_VAL) * 255.0f + 0.5f))               // Saturated, always output 0..255
 #define IM_FLOOR(_VAL)                  ((float)(int)(_VAL))                                    // ImFloor() is not inlined in MSVC debug builds
 #define IM_ROUND(_VAL)                  ((float)(int)((_VAL) + 0.5f))                           //
 
+// Error handling
+#ifndef IMGUI_USER_ERROR
+#define IMGUI_USER_ERROR(_EXPR, _MSG)   IM_ASSERT((_EXPR) && (_MSG))    // Recoverable User Error
+#endif
+
 // Debug Logging
 #ifndef IMGUI_DEBUG_LOG
 #define IMGUI_DEBUG_LOG(_FMT,...)       printf("[%05d] " _FMT, GImGui->FrameCount, __VA_ARGS__)
@@ -1047,9 +1056,7 @@ struct ImGuiDockNode
 struct ImGuiContext
 {
     bool                    Initialized;
-    bool                    FrameScopeActive;                   // Set by NewFrame(), cleared by EndFrame()
+    bool                    FontAtlasOwnedByContext;            // IO.Fonts-> is owned by the ImGuiContext and will be destructed along with it.
-    bool                    FrameScopePushedFallbackWindow;     // Set by NewFrame(), cleared by EndFrame()
-    bool                    FontAtlasOwnedByContext;            // Io.Fonts-> is owned by the ImGuiContext and will be destructed along with it.
     ImGuiIO                 IO;
     ImGuiPlatformIO         PlatformIO;
     ImGuiStyle              Style;
@@ -1064,20 +1071,23 @@ struct ImGuiContext
     int                     FrameCountEnded;
     int                     FrameCountPlatformEnded;
     int                     FrameCountRendered;
+    bool                    WithinFrameScope;                   // Set by NewFrame(), cleared by EndFrame()
+    bool                    WithinFrameScopeWithImplicitWindow; // Set by NewFrame(), cleared by EndFrame() when the implicit debug window has been pushed
+    bool                    WithinEndChild;                     // Set within EndChild()
 
     // Windows state
     ImVector<ImGuiWindow*>  Windows;                            // Windows, sorted in display order, back to front
     ImVector<ImGuiWindow*>  WindowsFocusOrder;                  // Windows, sorted in focus order, back to front
     ImVector<ImGuiWindow*>  WindowsSortBuffer;
     ImVector<ImGuiWindow*>  CurrentWindowStack;
-    ImGuiStorage            WindowsById;
+    ImGuiStorage            WindowsById;                        // Map window's ImGuiID to ImGuiWindow*
-    int                     WindowsActiveCount;
+    int                     WindowsActiveCount;                 // Number of unique windows submitted by frame
-    ImGuiWindow*            CurrentWindow;                      // Being drawn into
+    ImGuiWindow*            CurrentWindow;                      // Window being drawn into
     ImGuiWindow*            HoveredWindow;                      // Will catch mouse inputs
     ImGuiWindow*            HoveredRootWindow;                  // Will catch mouse inputs (for focus/move only)
     ImGuiWindow*            HoveredWindowUnderMovingWindow;     // Hovered window ignoring MovingWindow. Only set if MovingWindow is set.
     ImGuiWindow*            MovingWindow;                       // Track the window we clicked on (in order to preserve focus). The actually window that is moved is generally MovingWindow->RootWindow.
-    ImGuiWindow*            WheelingWindow;
+    ImGuiWindow*            WheelingWindow;                     // Track the window we started mouse-wheeling on. Until a timer elapse or mouse has moved, generally keep scrolling the same window even if during the course of scrolling the mouse ends up hovering a child window.
     ImVec2                  WheelingWindowRefMousePos;
     float                   WheelingWindowTimer;
 
@@ -1105,7 +1115,6 @@ struct ImGuiContext
     bool                    ActiveIdPreviousFrameIsAlive;
     bool                    ActiveIdPreviousFrameHasBeenEditedBefore;
     ImGuiWindow*            ActiveIdPreviousFrameWindow;
-
     ImGuiID                 LastActiveId;                       // Store the last non-zero ActiveId, useful for animation.
     float                   LastActiveIdTimer;                  // Store the last non-zero ActiveId timer since the beginning of activation, useful for animation.
 
@@ -1212,9 +1221,9 @@ struct ImGuiContext
     ImFont                  InputTextPasswordFont;
     ImGuiID                 TempInputTextId;                    // Temporary text input when CTRL+clicking on a slider, etc.
     ImGuiColorEditFlags     ColorEditOptions;                   // Store user options for color edit widgets
-    float                   ColorEditLastHue;
+    float                   ColorEditLastHue;                   // Backup of last Hue associated to LastColor[3], so we can restore Hue in lossy RGB<>HSV round trips
     float                   ColorEditLastColor[3];
-    ImVec4                  ColorPickerRef;
+    ImVec4                  ColorPickerRef;                     // Initial/reference color at the time of opening the color picker.
     bool                    DragCurrentAccumDirty;
     float                   DragCurrentAccum;                   // Accumulator for dragging modification. Always high-precision, not rounded by end-user precision settings
     float                   DragSpeedDefaultRatio;              // If speed == 0.0f, uses (max-min) * DragSpeedDefaultRatio
@@ -1242,7 +1251,7 @@ struct ImGuiContext
     ImVector<ImGuiSettingsHandler>      SettingsHandlers;       // List of .ini settings handlers
     ImChunkStream<ImGuiWindowSettings>  SettingsWindows;        // ImGuiWindow .ini settings entries
 
-    // Logging
+    // Capture/Logging
     bool                    LogEnabled;
     ImGuiLogType            LogType;
     FILE*                   LogFile;                            // If != NULL log to stdout/ file
@@ -1269,7 +1278,6 @@ struct ImGuiContext
     ImGuiContext(ImFontAtlas* shared_font_atlas)
     {
         Initialized = false;
-        FrameScopeActive = FrameScopePushedFallbackWindow = false;
         ConfigFlagsCurrFrame = ConfigFlagsLastFrame = ImGuiConfigFlags_None;
         Font = NULL;
         FontSize = FontBaseSize = 0.0f;
@@ -1278,6 +1286,7 @@ struct ImGuiContext
         Time = 0.0f;
         FrameCount = 0;
         FrameCountEnded = FrameCountPlatformEnded = FrameCountRendered = -1;
+        WithinFrameScope = WithinFrameScopeWithImplicitWindow = WithinEndChild = false;
 
         WindowsActiveCount = 0;
         CurrentWindow = NULL;
@@ -1306,12 +1315,10 @@ struct ImGuiContext
         ActiveIdClickOffset = ImVec2(-1,-1);
         ActiveIdWindow = NULL;
         ActiveIdSource = ImGuiInputSource_None;
-
         ActiveIdPreviousFrame = 0;
         ActiveIdPreviousFrameIsAlive = false;
         ActiveIdPreviousFrameHasBeenEditedBefore = false;
         ActiveIdPreviousFrameWindow = NULL;
-
         LastActiveId = 0;
         LastActiveIdTimer = 0.0f;
 
@@ -1842,8 +1849,7 @@ namespace ImGui
     IMGUI_API bool          IsMouseDragPastThreshold(int button, float lock_threshold = -1.0f);
     inline bool             IsKeyPressedMap(ImGuiKey key, bool repeat = true)           { ImGuiContext& g = *GImGui; const int key_index = g.IO.KeyMap[key]; return (key_index >= 0) ? IsKeyPressed(key_index, repeat) : false; }
     inline bool             IsNavInputDown(ImGuiNavInput n)                             { ImGuiContext& g = *GImGui; return g.IO.NavInputs[n] > 0.0f; }
-    inline bool             IsNavInputPressed(ImGuiNavInput n, ImGuiInputReadMode mode) { return GetNavInputAmount(n, mode) > 0.0f; }
+    inline bool             IsNavInputTest(ImGuiNavInput n, ImGuiInputReadMode rm)      { return (GetNavInputAmount(n, rm) > 0.0f); }
-    inline bool             IsNavInputPressedAnyOfTwo(ImGuiNavInput n1, ImGuiNavInput n2, ImGuiInputReadMode mode) { return (GetNavInputAmount(n1, mode) + GetNavInputAmount(n2, mode)) > 0.0f; }
 
     // Docking
     // (some functions are only declared in imgui.cpp, see Docking section)

imgui_widgets.cpp

@@ -549,7 +549,7 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
     if (g.NavActivateDownId == id)
     {
         bool nav_activated_by_code = (g.NavActivateId == id);
-        bool nav_activated_by_inputs = IsNavInputPressed(ImGuiNavInput_Activate, (flags & ImGuiButtonFlags_Repeat) ? ImGuiInputReadMode_Repeat : ImGuiInputReadMode_Pressed);
+        bool nav_activated_by_inputs = IsNavInputTest(ImGuiNavInput_Activate, (flags & ImGuiButtonFlags_Repeat) ? ImGuiInputReadMode_Repeat : ImGuiInputReadMode_Pressed);
         if (nav_activated_by_code || nav_activated_by_inputs)
             pressed = true;
         if (nav_activated_by_code || nav_activated_by_inputs || g.ActiveId == id)
@@ -6491,8 +6491,8 @@ void    ImGui::EndTabBar()
     ImGuiTabBar* tab_bar = g.CurrentTabBar;
     if (tab_bar == NULL)
     {
-        IM_ASSERT(tab_bar != NULL && "Mismatched BeginTabBar()/EndTabBar()!");
+        IMGUI_USER_ERROR(tab_bar != NULL, "Mismatched BeginTabBar()/EndTabBar()!");
-        return; // FIXME-ERRORHANDLING
+        return;
     }
     if (tab_bar->WantLayout)
         TabBarLayout(tab_bar);
@@ -6923,8 +6923,8 @@ bool    ImGui::BeginTabItem(const char* label, bool* p_open, ImGuiTabItemFlags f
     ImGuiTabBar* tab_bar = g.CurrentTabBar;
     if (tab_bar == NULL)
     {
-        IM_ASSERT(tab_bar && "Needs to be called between BeginTabBar() and EndTabBar()!");
+        IMGUI_USER_ERROR(tab_bar, "BeginTabItem() Needs to be called between BeginTabBar() and EndTabBar()!");
-        return false; // FIXME-ERRORHANDLING
+        return false;
     }
     bool ret = TabItemEx(tab_bar, label, p_open, flags, NULL);
     if (ret && !(flags & ImGuiTabItemFlags_NoPushId))