It doesn't return nsEventStatus_eConsumeNoDefault when it should. It returns nsEventStatus_eIgnore for almost every menu item. I've put a workaround for this in nsNativeBrowserWindow::DispatchMenuItem(). Feel free to remove it. There's still a double dispatch for the "About" item.

More info: this problem became visible after saari checked in a (wrong) fix in nsMacEventHandler::HandleMenuCommand().

After all these years, this Viewer bug became invalid.

beard, if you agree the resolution is correct, please mark this bug as verified. Thanks!

Why is it invalid?

I thought it was invalid because it only affects Viewer. The real problem, which was in nsMacEventHandler::HandleMenuCommand(), has been fixed.

beard, please could you help us to verify this bug or provide a testcase to verify it?

Try all of the menu commands. If any of them apparently execute twice (two windows, two about boxes, etc.) then the bug is still there. I haven't seen this problem for a while, so I believe it's fixed.

Don't see this problem anymore. Marking as verified.