FF: unable to type plain text (close link) after inserting a link

[Wiktor Walc]

Ok, this was a bit tricky because I did not understand why sometimes it doesn't work and sometimes works, but finally I found the way to reproduce it.

Using FF 3.5.7:

• go to ​http://ckeditor.com/demo
• click "New page" button
• type "testing 12345"
• select with a mouse "12345"
• open the "Link" dialog, type some url, close the dialog
• now the tricky part starts: point your mouse cursor in the middle of 12345 (between 3 and 4 for example)
• using right arrow key go to the end of word
• press space
• type some text
• result: pressing space did not end the link.

[Wiktor Walc]

Actually looks like a dup of #3375.