Floated TextImageFormats deleted fom a QTextEdit leaves a undeletable frame behind

A QTextImageFormat can be inserted as inline, left or right floated. After insertion, they can be deleted by keypress. But floated QTextImageFormats leaves a blank square behind them, that can not be removed, it looks like an anonymous frame.

I do not understand why QTextImageFormat inherits QTextCharFormat and not QTextFrameFormat - in fact the latter supports a lot of properties that one would expect for an image, while the former does not. For example floating positioning, the lack of which might be the cause for the extra frame?