Fixed a one frame glitch, when window claiming focus themselves on ap…

…pear, the title bar wouldn't use the focused color on that frame.

imgui.cpp

@@ -4515,6 +4515,12 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         if ((flags & ImGuiWindowFlags_Modal) != 0 && window == GetFrontMostModalRootWindow())
             window->DrawList->AddRectFilled(fullscreen_rect.Min, fullscreen_rect.Max, GetColorU32(ImGuiCol_ModalWindowDarkening, g.ModalWindowDarkeningRatio));
 
+        // Apply focus, new windows appears in front
+        bool want_focus = false;
+        if (window_just_activated_by_user && !(flags & ImGuiWindowFlags_NoFocusOnAppearing))
+            if (!(flags & (ImGuiWindowFlags_ChildWindow | ImGuiWindowFlags_Tooltip)) || (flags & ImGuiWindowFlags_Popup))
+                want_focus = true;
+
         // Draw window + handle manual resize
         ImRect title_bar_rect = window->TitleBarRect();
         if (window->Collapsed)
@@ -4569,7 +4575,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
             window->DrawList->AddRectFilled(window->Pos+ImVec2(0,window->TitleBarHeight()), window->Pos+window->Size, bg_col, window_rounding, (flags & ImGuiWindowFlags_NoTitleBar) ? ImDrawCornerFlags_All : ImDrawCornerFlags_Bot);
 
             // Title bar
-            const bool window_is_focused = g.NavWindow && window->RootNonPopupWindow == g.NavWindow->RootNonPopupWindow;
+            const bool window_is_focused = want_focus || (g.NavWindow && window->RootNonPopupWindow == g.NavWindow->RootNonPopupWindow);
             if (!(flags & ImGuiWindowFlags_NoTitleBar))
                 window->DrawList->AddRectFilled(title_bar_rect.Min, title_bar_rect.Max, GetColorU32(window_is_focused ? ImGuiCol_TitleBgActive : ImGuiCol_TitleBg), window_rounding, ImDrawCornerFlags_Top);
 
@@ -4656,10 +4662,9 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         if (window->AutoFitFramesY > 0)
             window->AutoFitFramesY--;
 
-        // New windows appears in front (we need to do that AFTER setting DC.CursorStartPos so our initial navigation reference rectangle can start around there)
-        if (window_just_activated_by_user && !(flags & ImGuiWindowFlags_NoFocusOnAppearing))
-            if (!(flags & (ImGuiWindowFlags_ChildWindow|ImGuiWindowFlags_Tooltip)) || (flags & ImGuiWindowFlags_Popup))
-                FocusWindow(window);
+        // Apply focus (we need to call FocusWindow() AFTER setting DC.CursorStartPos so our initial navigation reference rectangle can start around there)
+        if (want_focus)
+            FocusWindow(window);
 
         // Title bar
         if (!(flags & ImGuiWindowFlags_NoTitleBar))