Today, the Columns panel takes up about a third of the Data Explorer at typical IDE/screen widths.

It is possible to hide it, but it's not obvious (you need to drill into Layout in a menu that's on the opposite side of the Explorer).

Beta users can't find this and think that the Columns view cannot be hidden: https://github.com/posit-dev/positron-beta/discussions/113.

I propose that we provide an affordance for collapsing the Columns view that can be found on the Columns view itself -- e.g. a chevron on the divider bar, or an "x" button in the upper right of the view.