Not a bug, just a comment.
I was working on Linouse Desravine (https://en.wikipedia.org/wiki/Linouse_Desravine). If you look at the page, there are several categories (https://commons.wikimedia.org/wiki/File:Linouse_Desravine_page.png). When you open it up in Visual Editor, there is only one (https://commons.wikimedia.org/wiki/File:Linouse_Desravine_visual_editor.png). There's no problem adding categories, I added the birthplace one, but it's just odd.
The oddness of seeing just the one cat might be due to the page not following w:en:MOS:ORDER. When I put the page in MOS:ORDER (stub templates go last, so all the cats are together), then none of them are visible.
It's possible that this is phab:T251398, but it might be a different problem.
The problem was caused by a missing {{s-end}} template, which resulted in unbalanced HTML, which in turn resulted in everything on the page following the {{s-start}} template to be treated as part of a template transclusion and not being editable – including categories. I fixed it in this edit: .
Thanks. I suspected that whatever it was wasn't anything serious, but I wasn't sure what it could be.
