> > > There are still problems to overcome:
> > > - still no way found to get a context menu for the folder icons (Files,
> > Online, Groups);

I do not understand the difficulty- context menus for all menu items work the same way,
so once we know how to implement contect menus for histograms, other context menus are
done the same way. As an example, I added context menus to all non-histogram list tree
items.

> In the mean time, I copied&kludged code from TGFrame.cxx to make the popup menu pop
> at the pointer position.

RTFM of http://root.cern.ch/root/htmldoc/TGListTree.html#TGListTree:description shows
how to correctly position the popup menu without kludging the event handler. Commited.

> The other problem is multiple selection of histograms.

Short answer: Multiple selection of list tree items cannot be done. The code in
TGListTree::HandleButton(Event_t *event) explicitely enforces single-selection by
always unconditionally unselecting all items. I will have to bring this up with the
ROOT team.

K.O.