The skew interaction is activated for the current canvas pad by clicking on the Scale tab of the interaction control (3.1.3 Interaction Control) in the Control Window.
The scale interaction allows the copying of φ or Z scales between projections. After activating the scale interaction, a scale may be copied by dragging it from the source window into the target window. A φ-scale copy will only work between two projections which have their vertical axes representing φ. A Z-scale copy will only work between two projections which have their horizontal axes representing Z.
The scale interaction does not have a pop-up menu.