Dialog boxes only work when tablet is tipped! DDouble letterss? One of my Samsung Galaxy Tabs v10.1 will not accept certain dialog input unless the tablet is some other direction than right-side up (left portrait, right portrait or upside down all work fine). For example hold the power button to turn it off, it asks "are you sure you want to shutdown?" It ignores all touches including "Ok" or "Cancel".

Also when you use the keyboard it often inserts two letters on one key push.

Thinking that this HAS to be a software issue I rooted and installed clockwork Mod ROM manager and restored an image from another working tablet. No change. This is the weirdest issue to date with my tablet adventures. Any idea what is going on?

UPDATE: Samsung repair said the screen was bad. They didn't elaborate but at least I have a working tablet now!
I'd suggest a full wipe, maybe it's a glitch. Otherwise it sounds like a hardware problem. By the way, I have understood that it's a bad idea to use a Nandroid backup from another device since some device-specific information could be moved as well.