What window manager are you using and is the compositor running?

I've (hopefully) fixed the decorations issue in SVN by being explicit about disabling decorations rather than relying on the window type hint. If you can conveniently test this, that would be great.

The flickering is almost certainly due to a change I made that removed some very ugly code. Previously it also flickered, but the location was a lot closer to the desired position. If necessary I'll revert that change, but I'd like to do something a bit more elegant first.

Also, is the popup sticky for you and does it stay on top? These are the two other features that are likely to have been broken by my recent changes.

This is with metacity, no compositor.

Sticky and staysontop is fine, but the window decorations make the window movable and resizable, which is just wrong. Readding the set_decorated (...FALSE)
would help a little bit, but not really, since the window will still be movable/resizable by e.g Alt-F7. Try pressing Alt-F10 when the popup is open.

I can understand the desire to clean up code, but I'd rather have ugly code than broken behaviour...

Current trunk is undecorated again, thanks for that.
It still jumps initially, though

I've just fixed the jumping (by reverting the earlier changes). I had a nice elegant fix, but non-northwest window gravity doesn't seem to be handled too well by the gtk+/metacity combination right now.

I'm still not happy about the decoration suppression code, so I'm not closing the bug quite yet.