Some gtk widgets don't have associated X windows, so they just draw
on their parents. Because of this, they cannot receive events and
if they are incorrectly sized, they don't clip so you can get messy
overwritting etc. If you require more from these widgets, the
EventBox is for you.
At first glance, the EventBox widget might appear to be totally
useless. It draws nothing on the screen and responds to no
events. However, it does serve a function - it provides an X window
for its child widget. This is important as many GTK widgets do not
have an associated X window. Not having an X window saves memory
and improves performance, but also has some drawbacks. A widget
without an X window cannot receive events, and does not perform any
clipping on it's contents. Although the name EventBox emphasizes
the event-handling function, the widget can also be used for
clipping.
The primary use for this widget is when you want to receive events
for a widget without a window. Examples of such widgets are labels
and images.
GTK.EventBox()->set_usize(100,100)
GTK.Entry()->set_visibility()