Deletion of the last of the offered thumbnail choices can freeze that tab. Happens when using the new New Tab feature on Firefox v13.0.1, installed 6/17/12. I can still delete the entire New Tab screen and then start another. I am running Win XP+SP3 on an Acer Inspire One netbook with a 1024x600 screen. This seems to happen every time I try it. This morning's update informed me about this new feature, so I was trying it out. To reproduce: Click New-Tab and the 9 thumbnails almost fit the screen (pic1). I scroll down to see the bottom of the screen (pic2). I click the [X] to delete the bottom right thumbnail. The thumbnail images shift up a little, then the screen image freezes (pic3). I have screen images for pic1-pic3, if they might be useful.