Strange visual phenomenons are occurring that weren't occurring before.

When I close an application that was running in development environment, a picture of the form remains in the screen; in fact two copies, one smaller than the other as the toolbar is closed first but the image is somehow not refreshed. At taht point, as I move the data session window, it leaves a trail. Additionally, sometimes only, even after I click on the maximize box in upper right, meaning to make form resizeable, it does not become resizeable.

I think the problem is screen refreshment at the windows level. Any ideas? I exited the application several times and rebooted.

TIA,

Alex