It can be easely checked for browsers, caledars, music & video players, dialers, keyboards, etc.. but not with clock app.
one possible way - is choose which application to open on widget tap, but listing will be very long and also one app can have several subapps inside and which one should be started nobody knows...
if some users have problem with Tweaker usage and do not read manuals and guides, this option will confuse and can cause errors on the screen during setup.
if you will try to install https://play.google.com/store/apps/d...aultappmanager
you will understand what do I mean. It works but with errors. This will be happen if I implement the same.