Just want to thank you guys at Adblock for doing a good job. Perhaps my needs are simple, but it means a lot to me to be able to use my Gmail account in the way I used to - without those annoying flashing messages every few seconds, as I type. I even considered quitting Gmail and moving to a different email provider, until I realized that I could deal with the nuisance messages simply by using Adblock.
For anybody who wants know, here are the simple filters:
top title on new email:
Saving/saved message on a reply - has two class names at the same time (space separated), so two rules:
Send/delete confirmation (note: then you lose the ability to undo the send or delete!):