Camera gimbal window greyed out. Not able to setup the camera trigger

We are using a new cube + autopilot and have uploaded AC 4.4.2 firmware.
All the setup went well. The copter also flew well. But then we tried to setup the camera trigger.
But was surprised to see that the camera gimbal option was completely greyed out.

If I use an older autopilot with AC 4.4.2 firmware still same issue.
Whereas if I downgrade to a lower version up to 4.3.8 then the camera shutter tab with servo limits is visible.

I assume there is some bug in the firmware which is not allowing that to happen.
If there is any change in the setup then please let me know.

De-install mission planner. Install the lastest mission planner version.
Update to Arducopter 4.4.4.

The missing feature that you are looking for is on the mission planner side.