I created a little project to show the bug and ... it compiled!
So I investigated and found that in previous project I put the directory in 'debug' target, while in the test project, it was in the 'global' target.
Investigating more I found that the 'Policy' combo is set by default to 'Use project options only', while all other 'Policy's are set to 'Append target options to project options'.
So no bug, at least not there but now I ask a little change:
1) can this policy be set as the others by default?
2) when 'Use project options only' is selected, the directory list could be grayed out (not clearing the list, so that it can be reenabled when needed).
Thanks for you help!