Help me debug my search dropdown box

[Mark.B]

I have an annoying problem with my search dropdown box.

When you select tghe "Show Posts" radio button when using Firefox, the drop down disappears.

You can then click it again and the radio button is selected.

Switching back to "Show Threads" does not cause the same behaviour.

I know this is related to some custom template stuff because in the default style it doesn't do it. However I have tried manually re-pasting the default search box code into the navbar template and that doesn't help.

Reverting the navbar template doesn't fix it either, so the problem is not in there.

I have also tried disabling plugins and still no joy.

This is a difficult one to track down...so to start with, has anyone ever seen this behaviour before?