[FF] Multirange broken when command used several times

[Tobiasz Cudnik]

Multirange broken when command used several times.

Reproduction steps:

1. Use bold on 2 separate chunks of text.
2. Select part of 1st and part of 2nd chunk.

   <strong>^fo^o </strong>bar<strong> f^oo^2</strong>
   

3. Click "bold" button several times.

Depending on first selection range start, there are 2 possible misbehaviors:

1. Second selection will jump from proper selection to rest of previously bolded text (of 2nd chunk).
2. Second (or both) selections will disappear after second or third use of bold command, but still they will make some DOM modifications.

35sec screencast presenting this issue: ​http://pub.meta20.net/fck-multirange.ogg

Env: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.9) Gecko/2009042219 Iceweasel/3.0.9 (Debian-3.0.9-1)