This doesn't seem to work for me either - any help to set this up would be appreciated. Shift clicking to select multiple attributes then double click to resize to contents works well, but to do this automatically would be great. Additionally, this resize process needs to be done multiple times when editing, as it seems any tool that deletes a feature (delete, split, merge etc) will 'reset' the attribute table and all of its column sizes. I'm using version 2.8.2
I now have no issues with table sizing. I am on version 2.9.3 and I have just re-performed multiple table tests and edited various geometry data, with no behaviour that collapses columns, etc. I re-tried everything I can think of, including emulating my original issues and pre-collapsing tables, pre-collapsing/pre-expanding columns, then edited various features (lines, points, polys) to watch table behaviour. The result now is no columns 'reset' or do strange things when I edit data or set column widths, etc - they just stay the way I want (expect). For me the issue is resolved.
I'm not sure what exactly was implemented at 2.8, but I'm on 3.0.3 and I still have all these issues with various actions causing field widths to resize all the time and am unable to get multiple fields to resize at once, as in the GIF that KoryKramer posted on 07-06-2020.
I think this idea should still be open and not marked as implemented. The initial idea was about the ability to auto-fit the width of all fields in a table to the field content by default.
