Gtk::Image drawn incorrect inside Gtk::ScrolledWindow

[Kasper Peeters <kasper peeters phi-sci com>]

Hi,

I have a Gtk::ScrolledWindow with a VBox inside. Inside that Gtk::VBox,
there are various widgets, among which a number of Gtk::Image.

When I scroll down, I often see corruption/incorrect rendering of the
Gtk::Image widgets. When the window is forced to refresh (not sure how
to do that manually, but it sometimes happens when I switch desktops),
the image suddenly renders correctly.

A picture says more than a thousand words; see

  http://kasper.phi-sci.com/bug_screenshots.png

where the top one shows a corrupt image (the garbled formula below the
first blue block of text). The second one shows what happens after a
refresh.

Any idea what might be causing this, or if not, how to go about
debugging this? Thanks!

Kasper