By default you may notice that there is a slight delay when hovering your mouse over a Taskbar Thumbnail. Here is a neat registry hack that will allow you to speed it up.
First type regedit into the search box in the Start Menu and hit Enter.
Now navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced and right-click to create a new DWORD and name it ExtendedUIHoverTime.
Now double-click on it and give it a Decimal value of “1” click OK, close out of Registry Editor, then logoff and back on for it to go into effect.
When you come back, you’ll notice when you hover your mouse over a thumbnail of an open app on the Taskbar the preview pops up instantly with no delay.
Slow it Down
If for some reason you want to slow it down you can do that too. Just change the Decimal value to something else like 1000 which is milliseconds. Then the delay will be a lot longer. You can change the value to whatever you want for your needs. We’re not sure why anyone would want to slow the preview down, but you never know.
If you’re annoyed by the small delay that takes place when hovering over a thumbnail on the Taskbar, this neat registry hack will fix the annoyance. If you want to increase the size of the Thumbnail Previews check out our article on using Windows 7 Taskbar Thumbnail Customizer.