FullscreenUI: Fix incorrect background rect bounds

Author: stenzek

src/core/fullscreenui.cpp

@@ -1600,7 +1600,7 @@ void FullscreenUI::DrawPauseMenu()
 
   // background
   dl->AddRectFilled(ImVec2(0.0f, scaled_top_bar_height),
-                    ImVec2(display_size.x, display_size.x - scaled_top_bar_height - LayoutScale(LAYOUT_FOOTER_HEIGHT)),
+                    ImVec2(display_size.x, display_size.y - LayoutScale(LAYOUT_FOOTER_HEIGHT)),
                     ImGui::GetColorU32(ModAlpha(UIStyle.BackgroundColor, 0.9f)));
 
   DrawAchievementsPauseMenuOverlays(scaled_top_bar_height);