Comments + Internals: Selectable: decoupled internal flags and removed their menu / menu-item semantic as upcoming changes are requiring more flexibility.

.github/issue_template.md

@@ -13,7 +13,7 @@ SELECT "PREVIEW CHANGES" TO TURN THE URL ABOVE INTO A CLICKABLE LINK.
 
 XXX
 
-**Back-end/Renderer/OS:** _(if the question is related to inputs or rendering, otherwise delete this section)_
+**Back-end file/Renderer/OS:** _(if the question is related to inputs/rendering/build, otherwise delete this section)_
 
 XXX
 

TODO.txt

@@ -25,6 +25,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - window: increase minimum size of a window with menus or fix the menu rendering so that it doesn't look odd.
  - window: double-clicking on title bar to minimize isn't consistent, perhaps move to single-click on left-most collapse icon?
  - window: expose contents size. (#1045)
+ - window: using SetWindowPos() inside Begin() and moving the window with the mouse reacts a very ugly glitch. We should just defer the SetWindowPos() call.
  - window: GetWindowSize() returns (0,0) when not calculated? (#1045)
  - window: freeze window flag: if not focused/hovered, return false, render with previous ImDrawList. and/or reduce refresh rate. 
 !- scrolling: allow immediately effective change of scroll after Begin() if we haven't appended items yet.
@@ -39,6 +40,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - drawlist: would be good to be able to deep copy of ImDrawData (we have a deep copy of ImDrawList now).
  - drawlist/opt: AddRect() axis aligned pixel aligned (no-aa) could use 8 triangles instead of 16 and no normal calculation.
  - drawlist: rendering: provide a way for imgui to output to a single/global vertex buffer, re-order indices only at the end of the frame (ref: https://gist.github.com/floooh/10388a0afbe08fce9e617d8aefa7d302)
+ - drawlist: callback: add an extra void* in ImDrawCallback to allow passing render-local data to the callback (would break API).
 
  - main: considering adding an Init() function? some constructs are awkward in the implementation because of the lack of them.
  - main: find a way to preserve relative orders of multiple reappearing windows (so an app toggling between "modes" e.g. fullscreen vs all tools) won't lose relative ordering.

imgui.cpp

@@ -11220,9 +11220,11 @@ bool ImGui::Selectable(const char* label, bool selected, ImGuiSelectableFlags fl
         return false;
     }
 
+    // We use NoHoldingActiveID on menus so that use can click and hold on menu and drag to browse child entries
     ImGuiButtonFlags button_flags = 0;
-    if (flags & ImGuiSelectableFlags_Menu) button_flags |= ImGuiButtonFlags_PressedOnClick | ImGuiButtonFlags_NoHoldingActiveID;
+    if (flags & ImGuiSelectableFlags_NoHoldingActiveID) button_flags |= ImGuiButtonFlags_NoHoldingActiveID;
-    if (flags & ImGuiSelectableFlags_MenuItem) button_flags |= ImGuiButtonFlags_PressedOnRelease;
+    if (flags & ImGuiSelectableFlags_PressedOnClick) button_flags |= ImGuiButtonFlags_PressedOnClick;
+    if (flags & ImGuiSelectableFlags_PressedOnRelease) button_flags |= ImGuiButtonFlags_PressedOnRelease;
     if (flags & ImGuiSelectableFlags_Disabled) button_flags |= ImGuiButtonFlags_Disabled;
     if (flags & ImGuiSelectableFlags_AllowDoubleClick) button_flags |= ImGuiButtonFlags_PressedOnClickRelease | ImGuiButtonFlags_PressedOnDoubleClick;
     bool hovered, held;
@@ -11378,7 +11380,7 @@ bool ImGui::MenuItem(const char* label, const char* shortcut, bool selected, boo
     ImVec2 pos = window->DC.CursorPos;
     ImVec2 label_size = CalcTextSize(label, NULL, true);
 
-    ImGuiSelectableFlags flags = ImGuiSelectableFlags_MenuItem | (enabled ? 0 : ImGuiSelectableFlags_Disabled);
+    ImGuiSelectableFlags flags = ImGuiSelectableFlags_PressedOnRelease | (enabled ? 0 : ImGuiSelectableFlags_Disabled);
     bool pressed;
     if (window->DC.LayoutType == ImGuiLayoutType_Horizontal)
     {
@@ -11552,7 +11554,7 @@ bool ImGui::BeginMenu(const char* label, bool enabled)
         window->DC.CursorPos.x += (float)(int)(style.ItemSpacing.x * 0.5f);
         PushStyleVar(ImGuiStyleVar_ItemSpacing, style.ItemSpacing * 2.0f);
         float w = label_size.x;
-        pressed = Selectable(label, menu_is_open, ImGuiSelectableFlags_Menu | ImGuiSelectableFlags_DontClosePopups | (!enabled ? ImGuiSelectableFlags_Disabled : 0), ImVec2(w, 0.0f));
+        pressed = Selectable(label, menu_is_open, ImGuiSelectableFlags_NoHoldingActiveID | ImGuiSelectableFlags_PressedOnClick | ImGuiSelectableFlags_DontClosePopups | (!enabled ? ImGuiSelectableFlags_Disabled : 0), ImVec2(w, 0.0f));
         PopStyleVar();
         window->DC.CursorPos.x += (float)(int)(style.ItemSpacing.x * (-1.0f + 0.5f)); // -1 spacing to compensate the spacing added when Selectable() did a SameLine(). It would also work to call SameLine() ourselves after the PopStyleVar().
     }
@@ -11562,7 +11564,7 @@ bool ImGui::BeginMenu(const char* label, bool enabled)
         popup_pos = ImVec2(pos.x, pos.y - style.WindowPadding.y);
         float w = window->MenuColumns.DeclColumns(label_size.x, 0.0f, (float)(int)(g.FontSize * 1.20f)); // Feedback to next frame
         float extra_w = ImMax(0.0f, GetContentRegionAvail().x - w);
-        pressed = Selectable(label, menu_is_open, ImGuiSelectableFlags_Menu | ImGuiSelectableFlags_DontClosePopups | ImGuiSelectableFlags_DrawFillAvailWidth | (!enabled ? ImGuiSelectableFlags_Disabled : 0), ImVec2(w, 0.0f));
+        pressed = Selectable(label, menu_is_open, ImGuiSelectableFlags_NoHoldingActiveID | ImGuiSelectableFlags_PressedOnClick | ImGuiSelectableFlags_DontClosePopups | ImGuiSelectableFlags_DrawFillAvailWidth | (!enabled ? ImGuiSelectableFlags_Disabled : 0), ImVec2(w, 0.0f));
         if (!enabled) PushStyleColor(ImGuiCol_Text, g.Style.Colors[ImGuiCol_TextDisabled]);
         RenderArrow(pos + ImVec2(window->MenuColumns.Pos[2] + extra_w + g.FontSize * 0.30f, 0.0f), ImGuiDir_Right);
         if (!enabled) PopStyleColor();

imgui_internal.h

@@ -228,10 +228,11 @@ enum ImGuiColumnsFlags_
 enum ImGuiSelectableFlagsPrivate_
 {
     // NB: need to be in sync with last value of ImGuiSelectableFlags_
-    ImGuiSelectableFlags_Menu               = 1 << 3,   // -> PressedOnClick
+    ImGuiSelectableFlags_NoHoldingActiveID  = 1 << 3,
-    ImGuiSelectableFlags_MenuItem           = 1 << 4,   // -> PressedOnRelease
+    ImGuiSelectableFlags_PressedOnClick     = 1 << 4,
-    ImGuiSelectableFlags_Disabled           = 1 << 5,
+    ImGuiSelectableFlags_PressedOnRelease   = 1 << 5,
-    ImGuiSelectableFlags_DrawFillAvailWidth = 1 << 6
+    ImGuiSelectableFlags_Disabled           = 1 << 6,
+    ImGuiSelectableFlags_DrawFillAvailWidth = 1 << 7
 };
 
 enum ImGuiSeparatorFlags_