Volume out of sync when switching devices

[jorisw]

The app can misjudge the last known system volume setting, when changing volume after a change of audio device.

This can lead to painful volume jumps while using headphones.

Reproduce:

• Turn the volume up using this app
• Switch to using Bluetooth headphones
• The headphones are now using a lower volume set by the OS
• Hit the Volume Up key on your keyboard
• The volume now jumps significantly, based on what the app thought the last volume setting was, in a way that's bad for the ears.

Admittedly I last tested this on v1.6.8, but I could not find a reference to this problem in any change log since.