Hi, I am back. Tired, no nightly, but that target combo disappearing has been a problem for several months now. I have had it on my opensuse 10.2 since day one, it seems it popped up on linux in wx263, though someone now also seems to suffer from it in wx261 ...
EDIT : Workaround : click on the combobox but on the text of a target (so NOT the drop down arrow) and then select a choice by using the up/::down arrow keys on your keyboard