One column in DataGrid looks like that: <DataTemplate> <StackPanel> <Image MouseDown="OpenWindow" /> <Image MouseDown="func2"/> </StackPanel> </DataTemplate> In OpenWindow window is opened: it starts opening in foreground (in front of the window with DataGrid), but when creating UI ends it is placed behind window with DataGrid, which is not expected behavior. When I changed Image to Button and MouseDown to Click everything works as it should (opened window is placed in front of the one with DataGrid).