D&D in gtk

[hv1989 <hv1989 gmail com>]

Hi,

I need some help about D&D.

I have a gtkBox containing some icons. It is possible to move the
positions of the icons.
It works like this:

You click on an icon and I hide that icon and show an indicator of
where the icon will come. When you move over another icon it updates
the position of the indicator to position right before/after the icon
that got the move-signal. When the drop ends I hide the indicator and
moves the icon to that place.

So
- Every icon is a drop zone
- Every icon is a drag zone
- The gtkBox contains an extra icon (that is only a drop zone) that is
called an indicator.

Now I want that the indicator gets hidden when the dragged source
moves off the gtkBox.
How can I do that best?

greetz Hannes