Hi sanjibmandl, I'm afraid it's really a bit hard to understand quite what you mean. I think you're referring to an issue to do with 'Visualisation' (or in the USA 'visualization'). Note - Windows help on mine finds on;y the 2nd spelling.
You might try the Aero troubleshooter (search Windows Help for Visualization, read the text under
'Why are some visual elements being automatically turned off?', and then run the troubleshooter (link at the bottom).
Or in Control Panel, go to Performance Information and Tools, and click Adjust Visual Effects and see if 'Show Window Contents while Dragging is not checked. If you want window contents to remain displayed (better performance PC/graphics card), check it.
Post back and say if this solved your problem, or I else I suggest you post with a screenshot.