Open a Compose window using text-mode composition, rather than HTML mode, which is evil and kills kittens. Type some crap, then hold the space bar to fill up the rest of the line (typing any actual words is optional, but easier to illustrate, this behavior pops up with a full line of spaces too). Rather than wrapping to the next line, the cursor jumps to the last actual letter/character typed (or the beginning of the line, if you didn't type any actual letters/numbers/etc), and backspace doesn't *appear* to do anything until the line "unwraps" (or where it normally would unwrap, were it wrapping to start with), when the cursor then jumps to the end of the line, and moves backwards as expected. It's obviously deleting the spaces as it should, but with the cursor stuck until the line unwraps, it appears to do nothing. Just a wild guess, but is this related to the whole format=flowed thing?

I'm able to reproduce on version 1.0+ (20050319) (Windows XP). Reproducible: Always in text composition mode. Steps to reproduce: 1. Open a new Compose window using text-mode composition. 2. Begin a line in the body of the message by typing anything you want. 3. Press the spacebar until the cursor reaches the end of the line. Actual results: The cursor jumps back to the beginning of the block of spaces on the same line. Pressing the spacebar additional times does not move the cursor. Expected results: The cursor appears at the beginning of the next line no matter what character is typed.

This is a general plaintext editor issue that also effects html forms. *** This bug has been marked as a duplicate of 104674 ***