Issue:

WorkPlane tools disabled when 2D object is selected

This is not an issue. It is an 'As Designed' behavior of the application.

Changing WorkPlane can cause a lot of problems if object is selected in 2D mode.

Reason:

 - Inspector Bar values (pos X, pos Y) will become meaningless

 - Selection changes LCS after transformation, it is unacceptable in Selector 2D mode 

 - Reference point can be raised above the 2D object (Z > 0)

Most 2D draggers (2D selector, line tool etc.) do not allow work plane changes after starting (i.e. after first step/click or selection).