This edit will apply to all of the N sources...

[ocs]

This alert (and probably many others too) should have the standard suppression button.

While it is not suppressed, it should actually work Check please this scenario (2.14.0 (2922e78), far as I know, the newest one):

1. best to back up the database, for the subsequents steps might be somewhat destructive (the changes seemed not undoable at first, but it actually is a bit more elaborated)
2. open the Source list/editor
3. select more sources with different Source Types
4. click to the Source Type text field and press any letter
5. the “This edit will apply to all ...” alert shows. Click “Cancel”
6. click to any other field in the form, or press Tab. All the selected source types are lost.