Window, Focus, Popup: Fixed an issue where closing a popup by clicking another window with the _NoMove flag would refocus the parent window of the popup instead of the newly clicked window.

docs/CHANGELOG.txt

@@ -50,6 +50,8 @@ Other Changes:
   (It does not provide the docking/splitting/merging of windows available in the Docking branch)
 - Added ImGuiWindowFlags_UnsavedDocument window flag to append '*' to title without altering 
   the ID, as a convenience to avoid using the ### operator.
+- Window, Focus, Popup: Fixed an issue where closing a popup by clicking another window with the _NoMove flag would refocus
+  the parent window of the popup instead of the newly clicked window.
 - Window: Contents size is preserved while a window collapsed. Fix auto-resizing window losing their size for one frame when uncollapsed.
 - Window: Contents size is preserved while a window contents is hidden (unless it is hidden for resizing purpose).
 - Window: Resizing windows from edge is now enabled by default (io.ConfigWindowsResizeFromEdges=true). Note that 

imgui.cpp

@@ -6545,19 +6545,31 @@ void ImGui::ClosePopupsOverWindow(ImGuiWindow* ref_window)
     if (popup_count_to_keep < g.OpenPopupStack.Size) // This test is not required but it allows to set a convenient breakpoint on the statement below
     {
         //IMGUI_DEBUG_LOG("ClosePopupsOverWindow(%s) -> ClosePopupToLevel(%d)\n", ref_window->Name, popup_count_to_keep);
-        ClosePopupToLevel(popup_count_to_keep);
+        ClosePopupToLevel(popup_count_to_keep, false);
     }
 }
 
-void ImGui::ClosePopupToLevel(int remaining)
+void ImGui::ClosePopupToLevel(int remaining, bool apply_focus_to_window_under)
 {
     IM_ASSERT(remaining >= 0);
     ImGuiContext& g = *GImGui;
     ImGuiWindow* focus_window = (remaining > 0) ? g.OpenPopupStack[remaining-1].Window : g.OpenPopupStack[0].ParentWindow;
-    if (g.NavLayer == 0)
-        focus_window = NavRestoreLastChildNavWindow(focus_window);
-    FocusWindow(focus_window);
     g.OpenPopupStack.resize(remaining);
+
+    // FIXME: This code is faulty and we may want to eventually to replace or remove the 'apply_focus_to_window_under=true' path completely.
+    // Instead of using g.OpenPopupStack[remaining-1].Window etc. we should find the highest root window that is behind the popups we are closing.
+    // The current code will set focus to the parent of the popup window which is incorrect. 
+    // It rarely manifested until now because UpdateMouseMovingWindow() would call FocusWindow() again on the clicked window, 
+    // leading to a chain of focusing A (clicked window) then B (parent window of the popup) then A again.
+    // However if the clicked window has the _NoMove flag set we would be left with B focused.
+    // For now, we have disabled this path when called from ClosePopupsOverWindow() because the users of ClosePopupsOverWindow() don't need to alter focus anyway,
+    // but we should inspect and fix this properly.
+    if (apply_focus_to_window_under)
+    {
+        if (g.NavLayer == 0)
+            focus_window = NavRestoreLastChildNavWindow(focus_window);
+        FocusWindow(focus_window);
+    }
 }
 
 // Close the popup we have begin-ed into.
@@ -6569,7 +6581,7 @@ void ImGui::CloseCurrentPopup()
         return;
     while (popup_idx > 0 && g.OpenPopupStack[popup_idx].Window && (g.OpenPopupStack[popup_idx].Window->Flags & ImGuiWindowFlags_ChildMenu))
         popup_idx--;
-    ClosePopupToLevel(popup_idx);
+    ClosePopupToLevel(popup_idx, true);
 
     // A common pattern is to close a popup when selecting a menu item/selectable that will open another window.
     // To improve this usage pattern, we avoid nav highlight for a single frame in the parent window.
@@ -6636,7 +6648,7 @@ bool ImGui::BeginPopupModal(const char* name, bool* p_open, ImGuiWindowFlags fla
     {
         EndPopup();
         if (is_open)
-            ClosePopupToLevel(g.BeginPopupStack.Size);
+            ClosePopupToLevel(g.BeginPopupStack.Size, true);
         return false;
     }
     return is_open;

imgui_internal.h

@@ -1297,7 +1297,7 @@ namespace ImGui
 
     // Popups, Modals, Tooltips
     IMGUI_API void          OpenPopupEx(ImGuiID id);
-    IMGUI_API void          ClosePopupToLevel(int remaining);
+    IMGUI_API void          ClosePopupToLevel(int remaining, bool apply_focus_to_window_under);
     IMGUI_API void          ClosePopupsOverWindow(ImGuiWindow* ref_window);
     IMGUI_API bool          IsPopupOpen(ImGuiID id); // Test for id within current popup stack level (currently begin-ed into); this doesn't scan the whole popup stack!
     IMGUI_API bool          BeginPopupEx(ImGuiID id, ImGuiWindowFlags extra_flags);

imgui_widgets.cpp

@@ -5657,7 +5657,7 @@ bool ImGui::BeginMenu(const char* label, bool enabled)
     if (!enabled) // explicitly close if an open menu becomes disabled, facilitate users code a lot in pattern such as 'if (BeginMenu("options", has_object)) { ..use object.. }'
         want_close = true;
     if (want_close && IsPopupOpen(id))
-        ClosePopupToLevel(g.BeginPopupStack.Size);
+        ClosePopupToLevel(g.BeginPopupStack.Size, true);
 
     IMGUI_TEST_ENGINE_ITEM_INFO(id, label, window->DC.ItemFlags | ImGuiItemStatusFlags_Openable | (menu_is_open ? ImGuiItemStatusFlags_Opened : 0));
 
@@ -5694,7 +5694,7 @@ void ImGui::EndMenu()
     ImGuiWindow* window = g.CurrentWindow;
     if (g.NavWindow && g.NavWindow->ParentWindow == window && g.NavMoveDir == ImGuiDir_Left && NavMoveRequestButNoResultYet() && window->DC.LayoutType == ImGuiLayoutType_Vertical)
     {
-        ClosePopupToLevel(g.BeginPopupStack.Size);
+        ClosePopupToLevel(g.BeginPopupStack.Size, true);
         NavMoveRequestCancel();
     }