Plane command misbehavior
Entering command Plane[z=0] works the same whatever view have focus (2D, 3D, table, CAS)
Plane[x=0] only works when the 3D view have focus. An error is reported otherwise which does not mimic the mathematically behavior.
- use x+0 z=0
- always focus on 3D view first
When command Plane receives as argument a line from the xy plane, it should return the plane containing that line and orthogonal to the xy plane.