World setup header width changes between tabs

During world setup, there are three tabs: Overview, Ruleset, Saves. When you switch between overview and Ruleset, everything functions as intended. If you switch between anything and Saves, for some reason there is a change in the size of the header content causing the Q and E buttons to notably displace. There is no vertical change, only a horizontal narrowing of the headers and Q/E buttons.

I wonder what's going on under the hood to make it do that. The divisions of the functional space below is equal across all tabs but just the header is being janky.