Hello!

Today I was trying to display a slice plot of a function of three coordinates using SliceContourPlot3D and noticed an unexpected side-effect: local variables which were used inside this function remain in the system and retain their numerical values.

For example, running the very first example from the Documentation Center:

SliceContourPlot3D[
 Exp[-(x^2 + y^2 + z^2)], "CenterPlanes", {x, -2, 2}, {y, -2, 
  2}, {z, -2, 2}]

creates three local variables i.e. x, y and z with their OwnValues being 2., 2. and 2. respectively. It appears that these values correspond to the upper plotting bounds inside the SliceContourPlot3D function.

The worst thing is actually that I cannot clear these values and turn my x, y and z back into symbols - ClearAll[x, y, z] throws an error "Cannot clear local variable z". Is it a known bug / already reported issue? Are there wayarounds?