There are 90 degree rotation and 1 degree rotation.

90 degree rotation

Click the rotation button on the controller and rotate it 90 degrees.

Keyboard shortcut key
[PageUp] clockwise, [PageDown] counterclockwise

1) Rotate button

1 degree rotation

Hold down the Ctrl button and click the rotate button.

Or [Ctrl + mouse wheel]

Keyboard shortcut key
[Shift + PageUp] [Shift + PageDown]