A class called vtkInteractionCallback was defined twice: in vtkImplicitCylinderWidget.cxx and in vtkImplicitPlaneWidget2.cxx. This violates the one definition rule and can lead to undefined behavior.
This commit resolves the ambiguity by removing the callback from vtkImplicitCylinderWidget. vtkImplicitCylinderWidget does not actually require the callback; the code is leftover from a copy/paste of vtkImplicitPlaneWidget2. vtkImplicitPlaneWidget2 uses the callback to implement SetLockNormalToCamera(), which does not exist on vtkImplicitCylinderWidget.