Window: Fixed position not being clamped while auto-resizing (#5843)

docs/CHANGELOG.txt

@@ -139,6 +139,8 @@ Other Changes:
 - 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.
 - Window: Auto-fit size takes account of work rectangle (menu bars eating from viewport). (#5843)
+- Window: Fixed position not being clamped while auto-resizing (fixes appearing windows without
+  .ini data from moving for a frame when using io.ConfigWindowsMoveFromTitleBarOnly). (#5843)
 - 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

@@ -5987,7 +5987,7 @@ static bool ImGui::UpdateWindowManualResize(ImGuiWindow* window, const ImVec2& s
     return ret_auto_fit;
 }
 
-static inline void ClampWindowRect(ImGuiWindow* window, const ImRect& visibility_rect)
+static inline void ClampWindowPos(ImGuiWindow* window, const ImRect& visibility_rect)
 {
     ImGuiContext& g = *GImGui;
     ImVec2 size_for_clamping = window->Size;
@@ -6576,9 +6576,9 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
 
         // Clamp position/size so window stays visible within its viewport or monitor
         // Ignore zero-sized display explicitly to avoid losing positions if a window manager reports zero-sized window when initializing or minimizing.
-        if (!window_pos_set_by_api && !(flags & ImGuiWindowFlags_ChildWindow) && window->AutoFitFramesX <= 0 && window->AutoFitFramesY <= 0)
+        if (!window_pos_set_by_api && !(flags & ImGuiWindowFlags_ChildWindow))
             if (viewport_rect.GetWidth() > 0.0f && viewport_rect.GetHeight() > 0.0f)
-                ClampWindowRect(window, visibility_rect);
+                ClampWindowPos(window, visibility_rect);
         window->Pos = ImFloor(window->Pos);
 
         // Lock window rounding for the frame (so that altering them doesn't cause inconsistencies)