I am happy to announce that RichEdit now provides nice drag&drop...
It was the first widget I have "fixed", so in fact this also marks the relative maturity of D&D system in U++.
In fact, as there is no docs yet, I suggest anybody interested to examine RichEdit/Clip.cpp, where the D&D for RichEdit is implemented (190 lines to make RichEdit drag&drop with Word, not bad