Dunno if I’m doing something wrong, missing an option, but noticed when deleting unused tracks in a song which has a group present, the outcome is a first track which can’t be expanded to input note events / panning & volume columns.
On 3.3.2 on windows here, first make sure you have a project with grouped tracks on the most left of the pattern, then select ‘delete unused tracks’ from the top left like;
The outcome will be;
No matter what I try to do with the first track, I can’t get it to become a ‘normal’ track where you can input notes.
Nothing earthshatteringly breaking 
or what a ctrl+t can’t fix, but thought mentioning.