I've come across the same bug in the help a couple times. It was enough that I just wrote off the help app at first, but I gave it another try with some success on other help terms later, so I didn't quite give up on it, and now I'm confirming your bug.
One of many ways to reproduce:
1. Open help
2. Search for "startup"
3. Click the first link (it's file:///usr/share/gnome/help/users-admin/C/users-admin.xml#goscustsession-5)
4. It won't load, so click it again or any other link.
5. Window disappears.
I've come across the same bug in the help a couple times. It was enough that I just wrote off the help app at first, but I gave it another try with some success on other help terms later, so I didn't quite give up on it, and now I'm confirming your bug.
One of many ways to reproduce: /usr/share/ gnome/help/ users-admin/ C/users- admin.xml# goscustsession- 5)
1. Open help
2. Search for "startup"
3. Click the first link (it's file://
4. It won't load, so click it again or any other link.
5. Window disappears.