Problem of 3D object rotation using manipulators Some time ago I began to study Blender. I did not have problems. Recently, after the break, I downloaded version 2.79 and I immediately had a problem. I can not rotate a 3D object using the manipulator. Regardless of the choice of the arc, the blender rotates the object around the vertical axis Z. Attempts to mark another axis in the group of check boxes "Constraint Axis" do not help. Can someone help me? Thanks in advance.
In case anyone else has the same problem: Careful with Alt,  (comma) this shortcut enables Manipulate center points. With that enabled, rotation and scaling will not have any visible effect on the objects.