I found an odd thing today. In Thunderbird, my favorite open source email client, when I tried to move large numbers of emails (more than 800) from one folder to another there was a huge performance hit with one method versus another.

Trying to drag and drop 875 emails, Thunderbird took more than 3 minutes to process them. However when I tried to move the same emails but used ctrl-click (Mac not PC, remember) to choose the target folder, the emails moved in less than 20 seconds.

The difference is staggering. I am interested to know if anyone has seen this same behavior on other operating systems.