message: Fix div by 0 bug in imgui
diff: @@ -4543,7 +4543,8 @@ static void Scrollbar(ImGuiWindow* window, bool horizontal)
  // The grabable box size generally represent the amount visible (vs the total scrollable amount)
  // But we maintain a minimum size in pixel to allow for the user to still aim inside.
  - const float grab_h_pixels = ImMin(ImMax(scrollbar_size_v * ImSaturate(win_size_avail_v / ImMax(win_size_contents_v, win_size_avail_v)), style.GrabMinSize), scrollbar_size_v);
  + const float win_size_v = ImMax(ImMax(1.0f, win_size_contents_v), win_size_avail_v);
  + const float grab_h_pixels = ImMin(ImMax(scrollbar_size_v * ImSaturate(win_size_avail_v / win_size_v), style.GrabMinSize), scrollbar_size_v);
  const float grab_h_norm = grab_h_pixels / scrollbar_size_v;
  // Handle input right away. None of the code of Begin() is relying on scrolling position before calling Scrollbar().
  