When specifying structure queries, it is possible to search on Chemical Terms as well (via the little menu box in the lower left corner). However, the accessible list of CTs does not reflect the - in my case highly customized - list of CTs that comes up when one wants to add a new CT to a table. It is however possible to paste them into the query box and then perform the search. But to be able to do this one first has to define a substucture search, paste the CT into the CT query box, and then remove the substructure.
The obvious advantage of being able to search on customized CTs would be that they don't have to be precalculated in the database, but only be defined in the Options/Chemical Terms menu.
I hope you understand my suggestion.
Thanks for those suggestions. The intention of the chemical terms favourites is to be able to do this, and I should point out a few things:
1. the chemical terms favourites that appear in the structure query widget are iimited to those the have a boolean return type. This is because to be used as a filter in a query the chemical terms expression must evaluate to true or false. Expressions that produce numerical (e.g. logP) or text values cannot be used directly, but can usually be converted to a boolean expression (e.g. logP < 5). So if you add your favourite as a boolean return type then you will see it in the available expressions when you use the structure query widget.
2. You do not need to specify a structure query in order to run a chemical terms expression as a query. You can enter just a chemical terms expression only and run that as a search. Of course these searches may be relatively slow as the chemical terms expression is being evaluated for every structure.