hi all .yesterday my customer found a bug in my programme...It said that when he press the down button of scrollbar, and refresh the datagridview at the same time...the down button will disappear!!

I test it for a long time...but cant see it...so i increase the data of my grid.then the bug comes!!!

when i click the down button of scrollbar and hold on,then press the hot-key to refresh my grid.the scrollbar disappears....i t...