1. A control device for controlling a plurality of properties of light emitted from a light source, the device comprising: a touch-sensitive user interface, for visually indicating a range of available values representing at least one property and to enable a user to control said at least one property on the basis of a location touched on said touch-sensitive user interface, thereby providing the control device with user input; a communication unit for adjusting said at least one property by means of communicating, to the light source, control signals corresponding to said user input; a plurality of activation areas, each activation area being associated with at least one of said plurality of properties and being adapted, when activated, to cause said control device to enable the user to control the property associated with said activated activation area with said touch-sensitive user interface; a user interface visual appearance variation unit adapted to adjust the visual appearance of the user interface on the basis of the respective property associated with the activation area which includes a substantially circular and approximately planar light guide having a plurality of recesses, each of the recesses arranged to receive a light emitting element.