Prevent AggSeriesSlot columns from opening up in their own Slot Dialogs (e.g. from RDF Output config)
Bug Number: unfiled
Release notes (y/n): no
For Release Nums: 7.2.1 and 7.3

It had been possible to show an individual AggSeriesSlot column in its own 
Slot Dialog.  We don't currently intend to support this.  This could be done 
by adding columns from a multiple-column AggSeriesSlot to an RDF Output Device 
configuration and double clicking on one of those slot columns (after the 
first column).

See this illustration:
http://cadswes2.colorado.edu/~philw/2018/bugs/6068/Bug-ShowAggSerSlotCol-InOpenSlotDlg.png

Bug model bug6068.mdl.gz (an unrelated bug) is a tiny RiverWare 7.2 model 
with a single Output Device (RDF Output) which can be used to demonstrate 
and test this behavior.

See the changes in Q3GUI/Workspace.cpp, method:
 QMainWindow* Workspace::openSlot (Slot* slotPtr, bool inViewer=true);