Steps to reproduce:
- Open a page and go to Page options > Categories.
- (Add a category if none exist.) Edit a category to add a sort key.
- Save page.
- Check diff: no sort key was added. :-(
Confirmed in Firefox 32 and Safari 6.2 on Macs and Windows, so it's probably happening everywhere.
This doesn't seem to be bug 48555.
Version: unspecified
Severity: normal