Hover hint of "set default device" toggle button should be renamed

[Petr Gladkikh]

This problem is nagging me for years already and I believe it should be straightforward to fix.
This is usability issue. On both tabs "Output Devices" and "Input devices" at the top right corner of input and output devices' pads there's a button that allows to set default/preferred device if current system has more than one. These buttons are highlighted in the attached screen-shot.

The problem is that mouse hover message on this button says "Set as fallback" while it's action is exactly opposite. Namely, when button is depressed which normally means "activated" or "on" state the corresponding device becomes the default one. On the screen-shot attached first device is fallback while second device is default one.

So instead of "Set as fallback" the hover message on these buttons should say "Set as default" or "Set as preferred".

I've seen this behavior for several Ubuntu releases of both XUbuntu and default Ubuntu so I think exact version does not matter.

My current environment:
release
  Ubuntu 16.10
uname -a
  Linux localhost 4.8.0-38-generic #41-Ubuntu SMP Wed Feb 8 14:27:17 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux