fix issue, then it wasn't possible to remove functional blocks from
project using right click and popup menu.
The problem is that, PopupMenu was called using IDEFrame object and as
a result item in ProjectTree loosed focus and focus went to IDEFrame.
Therefore later functions couldn't detect which item in ProjectTree
was selected.
These classes are intended for use server-side.
e.g. in a django view.py :
from pyjs.jsonrpc.django import JSONService, jsonremote