Thunderbird inadvertent drag & drop triggered

[Jim Byrnes]

Running Ubuntu 10.04 and Thunderbird 13.x

Since upgrading to the 13 series of Thunderbird I have been seeing this 
strange problem.  When reading newsgroup messages the pointer will 
sometimes change to a hand with a document attached to it.  It looks 
like a drag & drop operations was triggered somehow, but when that 
happens the mouse is unusable.  The pointer moves but clicking or double 
clicking with either button does nothing.  The only solution seems to be 
ctrl-alt-del and then use the keyboard to restart Ubuntu.

It seems to happen when I am clicking to open a different newsgroup.

I wonder if anyone else is seeing this?

Thanks,  Jim