Steps to reproduce:

• go to your user profile Notifications Preferences and update AUTOMATIC PAGE WATCHING to Only when I create a new page, save the changes
• create a new page, then check the Notifications Preferences, on your user profile, under your Custom Filters: a new custom filter is added for your new created page
• then delete the page (even permanent delete)

Expected results:

• the Custom Filters (for the user Notification Preferences) should no longer display a filter for a page which no longer exists

Actual result:

• the Custom Filters for the user Notification Preferences is not deleted when the page was deleted (still shown on the user profile Notification Preferences - Custom Filters)

Tested on: XWiki Jetty HSQLDB 15.8