How to reproduce it :

• in Firefox, edit a content
• create a table with content
• try to select some table cell to collapse both
  > I see 2 behavior :
• the table cell is whole selected > that is like in Chrome
• only the borders of the table cell seems to be selected > that is what produce the bug, because if there is a content in the first cell celected, Firefox quit the editor to open in the same window an url composed by [my content].com

For example, I try to collapse 2 table cell. The first one contains "toto". So I quit the CMS without saving the modifications to go to the "toto.com" url.