1) Open Preferences->JBoss Tools->Web->JSF Pages
2) Choose any xhtml page, for example, FaceletBlank.xhtml and press remove button.
RESULT: Remove button becomes disabled and [default] label has gone (screenshot-1).

Well, I think, that Page should be deleted from the list of templates but nothing happens.

Another test case:
1) Choose JSFBasePage
2) Press "Set Default"
3) Press "Remove"
ASSERT: Confirmation dialog for page deleting should appear
RESULT: [default] label is deleted from JSFBasePage