The router preview item can be specific to the part that is being
tuned, rather than the whole net. It's also less visually noisy as
it doesn't dim/undim the rest of the board.
Using kigfx preview items for the status keeps us from having a bunch
of focus issues with the status popup window.
Autoscroll wasn't working on Mac because the status popup's panel
has the focus. This *may* also fix a problem on MSW of the auto-scroll
not being cancel-able.
Fixes https://gitlab.com/kicad/code/kicad/issues/11425
in most of files, including wx.h is not necessary, when only 2 or 3 wx files must be included.
Moreover, on windows, including wx.h sometimes create compil warnings about
shadowed vars defined in some specific windows headers.
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