ListBox does not raise MouseUp after column reordering

Dragging a ListBox column header to reorder the columns raises MouseDown, but MouseUp is missing when the mouse button is released. This prevents applications from reliably detecting when column reordering has finished.

MouseUp should fire exactly once after the drag completes, with the new column order available to the event handler. Normal row clicks and column resizing should continue to raise MouseDown and MouseUp normally.