Hi Vadim, others.

Using wxWidgets f3aa944 from git on Mac Tahoe 26.2

• I'm using wxTreeCtrl with only State Images by wxTreeCtrl::SetStateImages() with a wxVector<wxBitmapBundle> with 16x16 (in red) and 32x32 (in green for test) wxBitmaps
• I set states with wxTreeCtrl::SetItemState() for each Child Item (for test)
• I start the application on a HDPI display and it will use the 32x32 Bitmaps (1st image with 32x32 green state images)

• I then drag the application to a non-HDPI display and it will still use the 32x32 Bitmaps, which are now too big (2nd image with large 32x32 green state images)

• In debugger with wxWidgets source I think I traced it down to the wxWithImages function:

void WXHandleDPIChanged(wxDPIChangedEvent& event)
{
if ( HasImages() )
OnImagesChanged();
event.Skip();
}

• Because I only set State Images, HasImages() returns false and hence virtual wxGenericTreeCtrl::OnImagesChanged() is never called, which should handle DPI changes for the state images by m_imagesState.GetUpdatedImageListFor(this)
• If during initialisation apart from wxTreeCtrl::SetStateImages(BitmapBundleList) I also call wxTreeCtrl::SetImages(BitmapBundleList) (even though I don't use any Item Images), then the State Images will become DPI-aware correctly as expected (3rd images with 16x16 red state images)
  wxGenericTreeCtrl::OnImagesChanged() will be used to handle DPI changes for State Images

• So there is a workaround, but it might be worthwhile fixing ? (although it might be difficult in wxWithImages to judge that wxTreeCtrl will use OnImagesChanged() to update it State Images... ?)