Pressing F9 once or twice will close it but it shouldn't open and won't turn off. It doesn't seem to do this when there are no news groups subscribed to, but once there are news groups then opening the mail window also opens the sidebar
I can confirm this on build 2002062109 Did not happen on the last build I used which was about a week older.
How about Bug 153220?
Resolving as invalid. There is no build ID here, but sidebar was permanently removed from mailnews on Sept. 14th, 2002.
Status: UNCONFIRMED → RESOLVED
Last Resolved: 16 years ago
Resolution: --- → INVALID
You need to log in before you can comment on or make changes to this bug.