wrong icon

[rikona]

Running 16.04 fully updated. A while back I had a problem where
programs would "disappear" when minimized. At that time I got a number
of good suggestions and workarounds on this list that made it mostly
work correctly. Thank you all again. Since then I have seen something
else that made it look like they disappeared. What happens is that,
when minimized, they are associated with an icon on the left vertical
column that has NO RELATIONSHIP to the running program. The small white
triangle does appear on that icon, and when clicked brings back the
minimized program. Program A always goes to the same unrelated icon Z -
it is not random.

My question is how do I associate a program with the CORRECT icon in
the left vertical column so that it minimizes to the CORRECT icon and
not some strange unrelated icon? Most programs are correctly
associated, but a few are not. Some that still seem to disappear might
possibly be associated with an icon that perhaps is not in the left
vertical column.

All info much appreciated.

Thanks