Toggle in tree view without changing selection

["Jeffrey W. Baker" <jwbaker acm org>]

Howdy all, 

I am using the new GtkTreeView widget in my app, but I don't know quite
how to get the level of control I want.  I have multiple selection
enabled in the tree view, and one of my column renderers is a toggle. 
What I want is for the user to select multiple rows and be able to click
the toggles without changing the selection.  When the toggle is clicked,
every selected row should be toggled.

The mystery is what level do I need to hook to capture that click before
it changes the selection?  What signal on what widget needs to be
captured?

Bonus: how can I drag and drop a multiple-row selection?  Reorderable
rows and multiple selection are mutually exclusive in 1.3.13.

Regards,
Jeffrey