I thought of that. I checked the restore points, the dates on the video drivers, I uninstalled the video drivers that were running and installed the ones that were came with the laptop, etc. Nothing made any difference.

I have same issue with not only Tiles, but other software on Win8 too, especially Metro (Modern UI) apps (using ModernMix, but was happening before). Has to do with combination of Intel HD Graphics with ATI graphics on a Dell laptop. They don't play well together and sometimes they work fine, others not. From what I've seen it may have to do with the setting you choose, which GPU your app is set to use (there's a GUI to select that).

I think its a bug in windows modern UI (maybe with WPF too or lower level in DirectX), shouldn't behave that way in the 1st place

must be with offscreen compositing or something

in my case (with the Dell laptop), clicking the battery on the taskbar tray and selecting to use the "Dell" Power Plan, instead of the "High Performance" one seems to fix the issue. Probably need to compare in detail those plan settings to see in what exact setting(s) they differ