There are multiple suggestions. The problem could be alievated by making the popups wider, but ideally we want to fully remove the problem. One idea might be to look into the OOUI configurations.
A little more investigation:
- OOUI supports dialog (a.k.a. window) sizes "small" (300px), "medium" (500px), "large" (600px), "larger" (900px), and "full" (100%). Currently our code for the tour dialogs sets "large", but this is apparently ignored or not set correctly because the popups end up being 300px. Apparently this is an actual bug we should fix!
- Using the $container option as described in https://www.mediawiki.org/wiki/OOUI/Widgets/Popups#containerExample sounds great. I will continue the investigation @jkroll started.