Lister launched from toolbar button displays with empty space before file/folder names

I have a floating toolbar with some buttons that launch listers in specific folder locations. An example command editor "Function" line is: Go "D:\Data" NEW

There is one row of empty space along the top of the file/folder pane (the entire width of the pane) when such a lister is launched into list view from a toolbar button. That empty space stays there for the duration of the lister (through folder navigation), but goes away if switching to other than list view and then back again. This didn't happen in Opus 11--it is something that showed up with v12. Attached is a screenshot of just the lister file/folder view pane with the empty row of space.

This looks like this issue, which we are investigating: Column headers missing in initial tab list view (DO12.1)