Installing HP My Display appears to take over full control of the monitor brightness and does not allow the buttons on the monitor to function.
Reading https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/800-AIO-Front-panel-buttons/td-p/5059273 appears to suggest that there is a registry key that can fix this, but unfortunately both the links listed appear to be broken.
If anyone knows what this registry entry is, then please could they post a reply. We have tried updated drivers etc. but the ideal solution is that both the software (HP My Display) and the Monitor Buttons could control the brightness (and volume)
Regards
Ben