1) hide the status popup when the dialog is brought up
2) forward events from the popup to the canvas so hotkeys work
3) make sure diff pair radius is always 100%
4) fix greyed-out Miter style label
5) make L a hotkey so it works before you start dragging
Fixes: lp:1545856
* https://bugs.launchpad.net/kicad/+bug/1545856