+ GUI: remove more unused control pointers
+ GUI: remove more unused control pointers

jnetterf/calf,jnetterf/calf,zamaudio/calf-LR4,jnetterf/calf,zamaudio/calf-LR4,adiknoth/calf,zamaudio/calf-LR4,adiknoth/calf,zamaudio/calf-LR4,adiknoth/calf,zamaudio/calf-LR4,jnetterf/calf,jnetterf/calf,adiknoth/calf,adiknoth/calf