[gtkada] more questions on a ctree widget

[Ebert, Rolf]

1) Now, that I have managed to display a popup menu from a ctree widget, I'd
like it to be a *context* menu.  

Do I have to calculate the context myself using the X and Y coordinates of
the event, or are there any convenience functions which tell me the row
(node) and column? (comparable to the "select_row" signal)

2) I want to temporarily hide some rows (nodes) in the ctree.  Do I have to
rebuild the ctree from scratch applying my rules each time the rules change?
Or is there an attribute which I can simply set?