I'm the guilty one for the resizing handles (around tables, positioned elements and images) in Gecko's editor. It was a decade ago... I wanted a JavaScript-based implementation but Netscape's management wanted a C++ one to have the whole thing embeddable into an AOL project that you never heard of and never saw the light. Because of that, it's hardly manageable/extensible today and I decided to drop it for BlueGriffon (that's just a boolean to set to false on the editor) and switch to my own JavaScript-based implementation. I spent a short while on that last week-end and here's the first result (or see embedded video below). As far as I know, it's a first for the editor (I mean Gecko's).

Last detail, this should work even if CSS transforms apply to the table. Unfortunately, I filed a bug blocking it earlier today.