This looks like the "small motif windows" problem with compiz not a security padlock icon. In the screenshot, I'm pretty sure that the "locker sign" is actually the "Choose underlay" popup window. If you grab the bottom corner you can resize it.
In Ubuntu, for some reason the motif and compiz window manager sometimes don't play nicely together and pop up windows show up as small boxes that have to be manually resized. See also:
[
afni.nimh.nih.gov]
The recompiling trick stopped working at some point. I haven't had this problem since I switched to the 64-bit Ubuntu 9.04. Sometimes it works to disable hardware acceleration. (In the ubuntu menu: System > Preferences > Appearance, go to "Visual Effects" tab and select None).
--judd