Alt+Button click and events

[Toralf Lund <toralf procaptura com>]

I have an odd feeling that this is a stupid question because I'm 
overlooking something very obvious, but does Alt+Mouse button click have 
any special meaning in Gtk?

What I mean to say is, I have an application where I draw to a drawing 
area widget, and also handle various events for it "by hand" via the 
button-press-event and button-release-event signal, among others. This 
all works rather fine, but if the Alt button is pressed, my event 
handlers doesn't seem to "see" the button presses. Is there any obvious 
reason for this?

- Toralf