I have UserControl, which contains Canvas (in Grid).
When I just clicked on canvas event PreviewMouseLeftButtonDown or MouseLeftButtonDown works perfectly, but when I set canvas.Background = new ImageBrush(imgs);
and try to click on canvas, events doesn't raising. I tried to make same events for grid (canvas parent), but result was the same.
UPD1: canvas has children - rectangle (from System.Windows.Shapes) around cursor, maybe it somehow affect on events.