Can't stop Safari 5 downloads

I have two strange problems with Safari 5.1.3 (Lion 10.7.3), specifically with Downloads:

1. When a download is finished and I click on the magnifiying glass next to the name of the file I just downloaded, nothing happens. I can control-click for a menu that allows me to open or view in Finder, but the magnifying glass doesn't do anything.

2. If I start a download but want to stop it part-way through, clicking on "Stop download" does nothing, and the download continues. I have to exit out of Safari to stop the download.

I've tried reparing permissions, but that didn't help.

I'd appreciate any ideas!