Docking: child windows don't use style.ChildRounding.

imgui.cpp

@@ -6088,9 +6088,10 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->Pos = ImFloor(window->Pos);
 
         // Lock window rounding for the frame (so that altering them doesn't cause inconsistencies)
-        window->WindowRounding = (flags & ImGuiWindowFlags_ChildWindow) ? style.ChildRounding : ((flags & ImGuiWindowFlags_Popup) && !(flags & ImGuiWindowFlags_Modal)) ? style.PopupRounding : style.WindowRounding;
-        if (window->ViewportOwned)
+        if (window->ViewportOwned || window->DockIsActive)
             window->WindowRounding = 0.0f;
+        else
+            window->WindowRounding = (flags & ImGuiWindowFlags_ChildWindow) ? style.ChildRounding : ((flags & ImGuiWindowFlags_Popup) && !(flags & ImGuiWindowFlags_Modal)) ? style.PopupRounding : style.WindowRounding;
 
         // Apply window focus (new and reactivated windows are moved to front)
         bool want_focus = false;