We are using Honeywell Experion PKS DCS with C-300 controller and PMIO. We are using "Station" software for HMI interface. On any graphics screen there are menu & toolbar on the top to navigate & select a particular graphic. On toolbar, "Forward" & "Backward" buttons are configured to go to previous/next screen. In few operator station (workstation) these buttons are not working. Can anybody guide pl to resolve this issue.