BeginMenu(): Menus: Fixed a one-frame issue where SetNextWindowXXX data are not consumed by a BeginMenu().

+ Shallow tweaks to reduce diff of future branches. Removing early return also facilitate some changes.

docs/CHANGELOG.txt

@@ -154,6 +154,8 @@ Other Changes:
 - Menus, Nav: Fixed not being able to close a menu with Left arrow when parent is not a popup. (#5730)
 - Menus, Nav: Fixed using left/right navigation when appending to an existing menu (multiple
   BeginMenu() call with same names). (#1207)
+- Menus: Fixed a one-frame issue where SetNextWindowXXX data are not consumed by a BeginMenu()
+  returning false (specifically )
 - Nav: Fixed moving/resizing window with gamepad or keyboard when running at very high framerate.
 - Nav: Pressing Space/GamepadFaceDown on a repeating button uses the same repeating rate as a mouse hold.
 - Nav: Fixed an issue opening a menu with Right key from a non-menu window.

imgui.h

@@ -511,7 +511,7 @@ namespace ImGui
     IMGUI_API void          Image(ImTextureID user_texture_id, const ImVec2& size, const ImVec2& uv0 = ImVec2(0, 0), const ImVec2& uv1 = ImVec2(1, 1), const ImVec4& tint_col = ImVec4(1, 1, 1, 1), const ImVec4& border_col = ImVec4(0, 0, 0, 0));
     IMGUI_API bool          ImageButton(const char* str_id, ImTextureID user_texture_id, const ImVec2& size, const ImVec2& uv0 = ImVec2(0, 0), const ImVec2& uv1 = ImVec2(1, 1), const ImVec4& bg_col = ImVec4(0, 0, 0, 0), const ImVec4& tint_col = ImVec4(1, 1, 1, 1));
 
-    // Widgets: Combo Box
+    // Widgets: Combo Box (Dropdown)
     // - The BeginCombo()/EndCombo() api allows you to manage your contents and selection state however you want it, by creating e.g. Selectable() items.
     // - The old Combo() api are helpers over BeginCombo()/EndCombo() which are kept available for convenience purpose. This is analogous to how ListBox are created.
     IMGUI_API bool          BeginCombo(const char* label, const char* preview_value, ImGuiComboFlags flags = 0);
@@ -2971,7 +2971,7 @@ namespace ImGui
     // OBSOLETED in 1.81 (from February 2021)
     IMGUI_API bool      ListBoxHeader(const char* label, int items_count, int height_in_items = -1); // Helper to calculate size from items_count and height_in_items
     static inline bool  ListBoxHeader(const char* label, const ImVec2& size = ImVec2(0, 0))         { return BeginListBox(label, size); }
-    static inline void  ListBoxFooter() { EndListBox(); }
+    static inline void  ListBoxFooter()                                                             { EndListBox(); }
     // OBSOLETED in 1.79 (from August 2020)
     static inline void  OpenPopupContextItem(const char* str_id = NULL, ImGuiMouseButton mb = 1)    { OpenPopupOnItemClick(str_id, mb); } // Bool return value removed. Use IsWindowAppearing() in BeginPopup() instead. Renamed in 1.77, renamed back in 1.79. Sorry!
 

imgui_demo.cpp

@@ -1084,6 +1084,7 @@ static void ShowDemoWindowWidgets()
     IMGUI_DEMO_MARKER("Widgets/Combo");
     if (ImGui::TreeNode("Combo"))
     {
+        // Combo Boxes are also called "Dropdown" in other systems
         // Expose flags as checkbox for the demo
         static ImGuiComboFlags flags = 0;
         ImGui::CheckboxFlags("ImGuiComboFlags_PopupAlignLeft", &flags, ImGuiComboFlags_PopupAlignLeft);

imgui_widgets.cpp

@@ -6965,9 +6965,9 @@ bool ImGui::BeginMenuEx(const char* label, const char* icon, bool enabled)
 
     // Sub-menus are ChildWindow so that mouse can be hovering across them (otherwise top-most popup menu would steal focus and not allow hovering on parent menu)
     // The first menu in a hierarchy isn't so hovering doesn't get across (otherwise e.g. resizing borders with ImGuiButtonFlags_FlattenChildren would react), but top-most BeginMenu() will bypass that limitation.
-    ImGuiWindowFlags flags = ImGuiWindowFlags_ChildMenu | ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_NoNavFocus;
+    ImGuiWindowFlags window_flags = ImGuiWindowFlags_ChildMenu | ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_NoNavFocus;
     if (window->Flags & ImGuiWindowFlags_ChildMenu)
-        flags |= ImGuiWindowFlags_ChildWindow;
+        window_flags |= ImGuiWindowFlags_ChildWindow;
 
     // If a menu with same the ID was already submitted, we will append to it, matching the behavior of Begin().
     // We are relying on a O(N) search - so O(N log N) over the frame - which seems like the most efficient for the expected small amount of BeginMenu() calls per frame.
@@ -6975,7 +6975,7 @@ bool ImGui::BeginMenuEx(const char* label, const char* icon, bool enabled)
     if (g.MenusIdSubmittedThisFrame.contains(id))
     {
         if (menu_is_open)
-            menu_is_open = BeginPopupEx(id, flags); // menu_is_open can be 'false' when the popup is completely clipped (e.g. zero size display)
+            menu_is_open = BeginPopupEx(id, window_flags); // menu_is_open can be 'false' when the popup is completely clipped (e.g. zero size display)
         else
             g.NextWindowData.ClearFlags();          // we behave like Begin() and need to consume those values
         return menu_is_open;
@@ -7112,23 +7112,23 @@ bool ImGui::BeginMenuEx(const char* label, const char* icon, bool enabled)
     IMGUI_TEST_ENGINE_ITEM_INFO(id, label, g.LastItemData.StatusFlags | ImGuiItemStatusFlags_Openable | (menu_is_open ? ImGuiItemStatusFlags_Opened : 0));
     PopID();
 
-    if (!menu_is_open && want_open && g.OpenPopupStack.Size > g.BeginPopupStack.Size)
+    if (want_open && !menu_is_open && g.OpenPopupStack.Size > g.BeginPopupStack.Size)
     {
-        // Don't recycle same menu level in the same frame, first close the other menu and yield for a frame.
+        // Don't reopen/recycle same menu level in the same frame, first close the other menu and yield for a frame.
         OpenPopup(label);
-        return false;
     }
-
-    menu_is_open |= want_open;
-    if (want_open)
+    else if (want_open)
+    {
+        menu_is_open = true;
         OpenPopup(label);
+    }
 
     if (menu_is_open)
     {
         ImGuiLastItemData last_item_in_parent = g.LastItemData;
         SetNextWindowPos(popup_pos, ImGuiCond_Always);                  // Note: misleading: the value will serve as reference for FindBestWindowPosForPopup(), not actual pos.
         PushStyleVar(ImGuiStyleVar_ChildRounding, style.PopupRounding); // First level will use _PopupRounding, subsequent will use _ChildRounding
-        menu_is_open = BeginPopupEx(id, flags);                         // menu_is_open can be 'false' when the popup is completely clipped (e.g. zero size display)
+        menu_is_open = BeginPopupEx(id, window_flags);                  // menu_is_open can be 'false' when the popup is completely clipped (e.g. zero size display)
         PopStyleVar();
         if (menu_is_open)
         {