The Virtual Mirror command (which you can select under View in the context menu displayed by right-clicking on an empty zone of the graphics area) enables you to activate the virtual mirroring mechanism in the current view, so as to mirror the model about a symmetry plane.

A set of appropriate options to control the virtual mirroring mechanism is available in the Virtual mirror area of the View-Advanced category of the Document Properties.

To deactivate the virtual mirroring mechanism you can:

• Right-click on an empty zone of the graphics area with nothing selected and choose ViewNo Mirror in the context menu.
• Clear the Enable check box in the View- Advanced category of the Document Properties.

For details, see "Virtual Mirroring".