Restore the ListBox column resize cursor after custom cursor changes

The horizontal resize cursor can disappear from ListBox column dividers after an application switches between a custom cursor and MouseCursor.Default. This occurs in the bundled ListBox Dashboard example, which changes to a hand over its row action buttons. Column dragging still works, but the pointer remains an arrow over the dividers.

Returning to MouseCursor.Default should restore the control's normal context-sensitive cursors, including the resize cursor over column dividers and the text cursor over editable text.