I just double checked, there appears to be no way to isolate the IST from the ISV in the gen builder filters. IST and ISV are both included in the in-sample. OOS only includes data marked specifically OOS.
While ISV is actually an OOS during building, it does not seem to be included under OOS in any other area of SQX including the building filters and stagnation graphs. If you want to call it OOS in the progress tab that's fine with me but it might confuse someone.
for me its nothing more - IST/ISV/OOS
you are building on IST data and can rank and filter on IST/ISV/OOS
only 1 thing is different - you can restart gen algorith if ISV stagnates, this was added some time ago, because restart was possible only on IS