i did as the instructions said and still got those little boxes on the tash bar here is a pic of what i am talking about. I was installing something so please ignore that. I am refering to the box near the task bar.
Taskbar thumbnails. I used to be able to disable them, I have several tweaker apps that do that, but none of them work any more (changed by a Windows update?) Also the gpedit.msc method linked above didn't work, nor did the registry edit. Apparently they are part of Aero and if you don't like them you have to disable Aero. What you can do (I have just tried this and it worked) is to create / edit this registry key
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\ExtendedUIHoverTime
it's a DWORD and is the hover delay in milliseconds. Mine was set to 100 already. Choose decimal and set it to a ridiculously high value (I have 120000 which is a 2 minute hover before the thumbnail becoms visible).
