Big Sur 11.2.3 STILL not fixed!!
When using the Open/Save function (opening a window) we have to resize it every time.
The sidebar is NOT a sufficient width to read folder names.
With the latest Big Sur (11.2.3), the open/save window reverts to a default size, WHICH IS TOO SMALL!
So, now we all have to resize the window every time we open/save files.
BONEHEAD OVERSIGHT, APPLE!