Problem with popup menus and highlighted items in TreeView

[Gabriel Burt <gabriel burt gmail com>]

I have a TreeView (F-Spot's tag list) that has a popup menu.

If I have a tag (row) selected and then right-click on a different tag,
it first pops up the menu, then (the default handler) selects all the
tags in between the two tags.

The problem is I need to know how many tags are highlighted to customize
the popup menu, but because of the ordering of these operations, I get
the wrong value.  Is the only answer to not use the default handler and
do the selection logic (shift/ctrl) myself?

Thanks!

Gabriel Burt