On Dell XPS 9700 I have a Dell WD19 dock.

It used to work fine. 
Now when I have e dock station connected with the cable there WIFI is disabled
as it should

When I unplug Ethernet cable from the dock the wifi remains OFF and RFKILL
shows hard block.

When I plug the Ethernet cable back to the dock the wifi comes up for 2-3
seconds and sets up a connection and then I get e message that wifi gets
disabled and connection is switched back to Ethernet.

It used to work fine that unplugging the cable from dock would bring the wifi
up.

So having a dock station it is not possible to disconnect its ethernet and have
laptop enable Wifi.

It works ok in Ubuntu.