Simple questions on gtk+ application development

["Magiclouds Magicloud" <magicloud magiclouds gmail com>]

Dear all,
   I just start to learn to use gtk+, and there are something that I
can not find solutions on references. As below:
 1. What is the signal of GtkLabel on mouse hover, click and double
click? I user enter-notify-event and leave-notify-event for the hover
thing, and it does not work....
 2. How the select a node in treeview by the application? I tried
many ways like select, expand or so, none of them works....
 3. How to make a certain color transparent? I want a form that just
display some text on screen but no form box.... And, how to display a
text or image on screen without receive X events? I mean if I click
the image, it just like the image does not exist.

Thanks.