Table with pinned column containing row headers with Firefox
I tested with NVDA 2021.2 and FIrefox (93.0) and found that a table with a pinned column in column 1 that contains row header cells does not support navigation up and down column 1 using table navigation commands (Control+Alt+arrow). The row headers are read out correctly, however, when navigating up and down other columns. If I remove the row header cells, or move them to column 2, then navigation of the pinned column works well -- but of course my row header cells can now scroll out of view. NVDA works fine with Chrome and this table.
The pinning is through a css class
which is assigned in every row to the cell in column 1.
Here is a code pen with the problem case: https://codepen.io/azaitchik/pen/YzQxqeX
Is this a known problem? Is it the css?