Window: Fixed an issue where uncollapsed a window would show a scrollbar for a frame.

Amend / fix regression from 6e8e2c0

docs/CHANGELOG.txt

@@ -135,6 +135,7 @@ Other Changes:
   bar boundaries (bug in 1.88). (#5652).
 - Tabs: Enforcing minimum size of 1.0f, fixed asserting on zero-tab widths. (#5572)
 - Window: Fixed a potential crash when appending to a child window. (#5515, #3496, #4797) [@rokups]
+- Window: Fixed an issue where uncollapsed a window would show a scrollbar for a frame.
 - IO: Added ImGuiMod_Shortcut which is ImGuiMod_Super on Mac and ImGuiMod_Ctrl otherwise. (#456)
 - IO: Added ImGuiKey_MouseXXX aliases for mouse buttons/wheel so all operations done on ImGuiKey
   can apply to mouse data as well. (#4921)

imgui.cpp

@@ -6447,6 +6447,9 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->DC.MenuBarOffset.x = ImMax(ImMax(window->WindowPadding.x, style.ItemSpacing.x), g.NextWindowData.MenuBarOffsetMinVal.x);
         window->DC.MenuBarOffset.y = g.NextWindowData.MenuBarOffsetMinVal.y;
 
+        bool use_current_size_for_scrollbar_x = window_just_created;
+        bool use_current_size_for_scrollbar_y = window_just_created;
+
         // Collapse window by double-clicking on title bar
         // At this point we don't have a clipping rectangle setup yet, so we can use the title bar area for hit detection and drawing
         if (!(flags & ImGuiWindowFlags_NoTitleBar) && !(flags & ImGuiWindowFlags_NoCollapse))
@@ -6458,6 +6461,8 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
             if (window->WantCollapseToggle)
             {
                 window->Collapsed = !window->Collapsed;
+                if (!window->Collapsed)
+                    use_current_size_for_scrollbar_y = true;
                 MarkIniSettingsDirty(window);
             }
         }
@@ -6471,8 +6476,6 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
 
         // Calculate auto-fit size, handle automatic resize
         const ImVec2 size_auto_fit = CalcWindowAutoFitSize(window, window->ContentSizeIdeal);
-        bool use_current_size_for_scrollbar_x = window_just_created;
-        bool use_current_size_for_scrollbar_y = window_just_created;
         if ((flags & ImGuiWindowFlags_AlwaysAutoResize) && !window->Collapsed)
         {
             // Using SetNextWindowSize() overrides ImGuiWindowFlags_AlwaysAutoResize, so it can be used on tooltips/popups, etc.

imgui.h

@@ -23,7 +23,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM > 12345')
 #define IMGUI_VERSION               "1.89 WIP"
-#define IMGUI_VERSION_NUM           18832
+#define IMGUI_VERSION_NUM           18833
 #define IMGUI_HAS_TABLE
 
 /*