I would welcome the option to mirror glyphs in the preview panel.
When working, I like to rotate (180˚) or mirror my outlines to check.
Now I use a component.
180° rotation is not possible at the moment, but you can flip vertically with the “F” button in the preview area toolbar.
Thank you. I know the F function 
Are you planning to incorporate other rotations in the future ?
It’s on the list, but not very high up.