The Multi-Monitor Sync (MMS) function is likely turned on. When MMS is enabled, DDM can only fully control the first monitor in the daisy chain.
- Check the Multi-Monitor Sync setting within DDM.
- If MMS is ON, turn it OFF to regain full individual control over all daisy-chained monitors.
If that didn't work: Ensure DDC/CI is enabled on all monitors in the chain via the on-screen display menu (Display Info > DDC/CI). DDM uses the DDC/CI channel to communicate.
Heads up: With MMS off, you can select and control individual monitors from the drop-down list in the DDM Quick Settings dialog. A brief icon will flash on the selected monitor for identification.