If you turn on 'Enable Custom Toolbars', and then change to, say, the BiDi build, or a new version with a new button, the new buttons don't appear on your toolbars, and there is no UI to warn you. This has caused problems -- the thread on the user list about BiDi support not working largely comes from this. (And Hub's assumption that those buttons always appear on BiDi builds is wrong, for this reason.)
There is obviously a bug here somewhere, but it's not obvious to me where, so I'm posting here rather than filing in bugzilla. Could custom toolbars be stored as differences from the standard? Or the standard set recorded so that you get a warning if the standard set supplied by the app is different from the one you changed against? Obviously, warning whenever the standard set is different from your current set is the wrong thing to do. Custom toolbars should certainly default to 'off', given this, but I've not used default prefs for a long time, so I can't remember what the current situation is. David Chart
