Same outcome in safe mode? Hold Shift when you launch TB. Does it happen also with replies or just forwards? Do you send by clicking the Send button or File/Send Now (Ctrl+Enter)?

Didn't completely solve the problem. Ran many tests mostly in the safe mode. Now in the normal mode the send button is greyed out when attempting to forward or reply.

When you Forward, Send is greyed out until you enter a recipient, but not with Reply, as the recipient is the original sender.

If safe mode doesn't solve it 'completely', what does it fix and what does it not? What are your Extensions, TB version?

I discovered my problem, when I clicked of forward or Reply sometimes two Write windows were displayed. So when I forwarded the message the second write window displayed. I slowed my mouse down and seem OK now. Thanks for the help.

The solution was to replace my mouse that had an intermittent left mouse switch. If you get this proplem check or replace your mouse.