Two or three weeks ago I sent you a message direct (not through forum), pointing out that after typing a Forum message and clicking preview, and, using my computer back button to correct the message, the message is completely deleted

You say -

"To make corrections, please use "Back" button in your browser."

Once upon a time this worked perfectly and it went back to the original. Now it just completely deletes the message. To save typing the whole message again I now save what I have typed before using the back button.

Surely it would be a good move for you to either fix this problem or stop telling us to use our computer back button.