BO XI R2 Webi merged dimension icon was greyed out

In case of multiple data providers we can link common dimensions
but while getting data or synchronizing can we add all objects
in the report panel(i.e. in a tabel)
I think we can get measure and detail objects in the report.But
we can not have dimension objects from 2nd DP in the same table.
Am I right?
I tried the same thing in BO XI R2 Webi, but in webi merged
dimension icon was greyed out.Probably I missed something!! So I
tried in DeskI and it worked well for measure objects.But I have
lot of dimensions from 2nd DP which I need to show in the
report.Should I have to convert them in Detail objects?