Dual-pan/combined-pan sliders + controller

Hey all

Is there a way to switch between controlling the left and the right pan sliders in dual/combined mode? My Presonus FaderPort has one rotary knob for controlling pan and it works fine in mono mode. When in stereo mode however, it will always control the left pan slider. Is there a way to switch between the left and right pan sliders? Some modificator key or the like? I couldn’t find anything in the manual besides pressing [Alt], but this doesn’t work together with the controller :question: