Incorrect scrollbar calculation: plus should be replaced by minus

[mekhontsev]

imgui/imgui.cpp

Line 4675 in 486f0a8

window->ScrollbarY = (window->SizeContents.y > size_y_for_scrollbars + style.ScrollbarSize) && !(flags & ImGuiWindowFlags_NoScrollbar);

[ocornut]

Thank you, it looks like a bug introduced in c36e586 (I replaced + ItemSpacing.y - ScrollbarSize by + ScrollbarSize. Fixed now.

It's easy to confirm by resizing this window manually and comparing how the ScrollbarY appears depending on whether ScrollbarX is enabled.

ImGui::Begin("Test #1574", NULL, ImGuiWindowFlags_HorizontalScrollbar);
ImGui::Button("##xxx", ImVec2(500,500));
ImGui::End();

Thank you!

[ocornut]

Very surprisingly, this got accidentally broken back in a0994d7 in 2019 during a refactor of another thing (to a lesser extent than the original report).
Fixed again with 6cefd4f.
Added a test ocornut/imgui_test_engine@45c1fbb