Judging Feature Proposal/Request: Show/Hide used/unused columns in TAStudio

When it comes to judging various systems, showing all the possible input columns in TAStudio can make following an author's inputs difficult, as it is often not feasible to fit all the possible input columns on-screen at any given moment. This can sometimes make folowing what an author did more tedious as it requires one of the following approaches:

1. Pausing the playback for every vertical screen of frames and then laterally scrolling through all input possibilities to see where the actual used inputs are
2. Grouping input columns into used/unused and keeping all the used input columns together within TAStudio in an attempt to fit them all on the screen at once. While this can be done by manually turning off any unused column from the "Columns" menu, this still requires manually observing the entirety of the run simply while watching for where inputs are/aren't in the run in order to know if a column is even used in the first place.

We currently have a 'show keys' option in the "Columns" menu of TAStudio that toggles all the keys as shown/hidden, but it does not distinguish if a particular input column is used within the run.

Would it be possible to get an option under "Columns" to either of the following?

• show only used input columns
• hide unused input columns

I realize this may require some significant colding to allow BizHawk/TAStudio to programmatically parse a .bk2 fully to know which input columns are used, but I figured I'd ask anyway.

Moved from https://github.com/TASVideos/tasvideos/issues/2232.

Start in TAStudio's Columns menu and trace the existing “show keys” option to understand how columns are shown or hidden. Determine how a .bk2 run can identify input columns used anywhere in the run; done means an option can show only used columns or hide unused ones while preserving current column controls.