Describe the feature

Make the left panel of the options window either 1.5 to 2x the current width, or customisable.
Currently long category names get truncated making it difficult to know which one to use when you have category - expansion
Example:

Describe the implementation

Best:
There is currently a separator between the panes that is clickable, but doesn't do anything when you click it. Ideally this would be dragable to resize the pane widths (and remember what you drag it to).
Middle:
Set the left hand panel width in options
Minimum:
Increase the width in the addon code, don't make it customisable

This whole experience is slated for a major overhaul -- this will come in a future update as we migrate away from Ace Config and build a better forms API.