Okay, found the problem... It's a Pete bug (September 8, 2010... That's basically 2 weeks after Wedge was started!!)
If Wysiwyg is enabled by default, then the quick reply box is also in Wysiwyg by default.
Wedge thinks otherwise, though, and when you switch to the full editor, it requests a mode change from text to Wysiwyg. Because the text mode has no content (it's all in the contentEditable div), the div is thus replaced with empty content.
I've simply removed the couple of lines that requested the change. It seems to work here. I'll have to test in non-Wysiwyg mode, though... :^^;:
:edit: Working, too.