After creating a simple window/widget layout with Page (page.sourceforge.net)
I found that the listbox curselection() call returns the proper index when releasing Button-1.
When hit, it returns the previous index (the item which we just leave).
Becasue of some timer activities I'd like to get the clicked index at click-time, instead of release-time. Can somebody help me how could I do that? Thank you
Bind to the event <<ListboxSelect>> instead of <1>, this event will fire after the current selection has been updated. 
If you genuinely need for the binding to work literally on a press of the mouse button you will have to rearrange the order of the bind tags for the widget.
Getting Tkinter listbox item when hit Button-1