Hi there,
first: You really need a "Bugs" category 
I'm working with your editor since the relaunch of our website and it's a great tool.
Here are two bugs I am having problems with:
If you create a table with a header and you use the arrow to expand it to the right it appears that where the <th></th> should be there comes <td></td> 
Another, for me very annoying thing: What the hell does this editor have with breaks in html ? I'm going insane on that errors that are made up out of thin air 
example: copy this in the editor:
Ihr kennt ja die Linien auf dem Feld die ein Rasenmäher hinterläst.
Wenn ihr an der gegnerischen Hälfte eineinhalb Linien vor den großen Mittelgreiß geht und mit einem Heber schießt trefft ihr immer ins Tor.
Ihr müsst aber auch in der Mitte von der Breite des Spielfeldes stehen und schauen,
dass ihr mit dem Heber zu einem Stürmer oder anderen Mitspieler passt.
I am getting errors on nearly every break where an empty line follows. And thats simply annoying 
It somehow seems that the editor simply doesn't like "my" breaks, but when I do them one-by-one in the editor itself it works -.- but haha, nice hours of work 
edit: Bug 3:
If you have an element like <h5>whatever</h5> and you delete it (the whole line) in the "no-code" view, the <h5></h5> persists and whatever you write or move over next in this line will get the <h5></h5> effect
I am having these problems in build 19417 aka 2.6.2.
Greetings
BugGrabber