A right click on a process flow activity from the "People Sub Flows" category (Walk, Wait in Line, Excort Person, Transport Person, Move Equipment) doesn't open the usual context menu. Instead, FlexSim behaves as if the right mouse button is held down, i.e. when holding the left mouse button to drag the view, it will zoom in and out.
This happens in both the default and the HC environment. The error was seemingly introduced in some version of 21.2.
21.1.5 works normally.