Scrollbar: Fix for ScrollbarY enable check after ScrollbarX has been enabled. (#1574) Looks like a bug introduced in c36e586cce.

imgui.cpp

@@ -4672,7 +4672,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
             window->ScrollbarY = (flags & ImGuiWindowFlags_AlwaysVerticalScrollbar) || ((window->SizeContents.y > size_y_for_scrollbars) && !(flags & ImGuiWindowFlags_NoScrollbar));
             window->ScrollbarX = (flags & ImGuiWindowFlags_AlwaysHorizontalScrollbar) || ((window->SizeContents.x > size_x_for_scrollbars - (window->ScrollbarY ? style.ScrollbarSize : 0.0f)) && !(flags & ImGuiWindowFlags_NoScrollbar) && (flags & ImGuiWindowFlags_HorizontalScrollbar));
             if (window->ScrollbarX && !window->ScrollbarY)
-                window->ScrollbarY = (window->SizeContents.y > size_y_for_scrollbars + style.ScrollbarSize) && !(flags & ImGuiWindowFlags_NoScrollbar);
+                window->ScrollbarY = (window->SizeContents.y > size_y_for_scrollbars - style.ScrollbarSize) && !(flags & ImGuiWindowFlags_NoScrollbar);
             window->ScrollbarSizes = ImVec2(window->ScrollbarY ? style.ScrollbarSize : 0.0f, window->ScrollbarX ? style.ScrollbarSize : 0.0f);
         }