Rotating a layer
It may sometimes be useful to rotate a single layer as opposed to the whole canvas. Pixen provides a simple method for rotating a single layer by 90° either way or 180°.
To rotate a layer:
Right-click (or control-click) the layer you'd like to rotate and choose the magnitude from the Transform Layer submenu
or
Select the layer you'd like to rotate in the layers drawer and use the commands in the Layers > Rotate Layer menu.