How much ram do you have? Have you tried restarting everything? I cannot re-create the issue here.
I have 8 MB of RAM. I restarted all the software, but not my computer.
It is in the left column that I am having the problem.
There was a previous discussion thread where a user on Mountain Lion was having the same issue, but it wasn't resolved in that discussion thread either.
I haven't upgraded to Mountain Lion yet, so I cannot recreate the problem. Sorry!
I am not running Mountain Lion. As I stated at the the beginning I am running Snow Leopard.
But I know from previous posts that I am not the only person having this problem, including someone who is running Mountain Lion.
Could this be a server problem?