When previewing a user JS page, say User:Catrope/vector.js the code submitted for preview is loaded, but the other user JS files (User:Catrope/common.js in this case; both when previewing a third user JS file) are not loaded.

This is because the code providing the JS preview has logic to not load the user module (containing all user JS) when previewing. This was a good thing when there was only one user JS file, but now there's two, and it would've already failed when previewing a non-skin JS file even before the introduction of common.js

Version: 1.18.x
Severity: enhancement