<?> Fields : how to get rid of them ?

Hello !

I'm using a trial version of EM2, in order to see if I should upgrade my old version 1. I would do so, were it not for this problem :

I can't get rid of 4 "ghost" annotations fields. Their labels show only "<?>". Screenshot here. In the View Options window, only the field "File name" is selected.

Any idea, how I could solve this ?
Thank you
Thierry