but try this.
Open up Display Properties, (right click the desktop, select Properties), then on the Appearance tab, click the ''Effects'' button.
See if changing the option ''Show window contents while dragging'' changes the effect you are seeing.
I dont think this is a problem but it is an option:
when i open any box, internet option box for example(specially Task Manager box), when i move this box across the screen there is a shadow moving behind the boxi have read how to stop this option but really forget about it,anybody can help?