Its because you changed the workplane and the plane and view don't match.The easiest way to reset things is to right-click anywhere in the drawing area, then choose the view you want, then click 'Plane by active view'.
This is what I do in Tcad ProProf, Tcad Deluxe should be the same. I don't use Tcad as much now that I've switched to Fusion.
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Edited By Gary Wooding on 23/02/2020 08:11:25