Piedock should adapt to resolution changes and xrandr orientations changes

[bjonnh]

Piedock doesn't seems to adapt well when resolution is changed or a new screen is added/removed. It must be restarted each time to appear correctly at mouse cursor position.

[markusfisch]

Well, that's right. I considered this case to be very seldom so a restart seemed okay. Will fix it with the next release, which should happen this month or so. Thanks for pointing out!