I did an update from 18.04->18.10->19.04 Ubuntu. After the update the switch applications or switch windows functionality is not working. Tried alt-tab and super-tab.
I tried to reset the keyboard shortcut in settings and tried again after setting it. still the same. All the other shortcuts with alt works. For ex: alt-f4 close the window. But when I replaced alt-f4 with alt-tab it didn't work.