@Wayne-TP 

I understand the detection zone cannot keep original zone during motion which actually does not make sense since original zone can be out of range when camera moves.

Let me rephrase my request then.

First here is my understanding.

The zone detection set works when not motion tracking.

When motion tracking starts the whole screen is considered as zone detection.

Assuming above is correct (please correct if I am wrong) here is what I would like to have.

When motion tracking starts do not consider the whole screen but only a part of it as zone detection. Seems possible only in software (no firmware change needed).

Then as a part of screen, in my case I would need full width and 20% of high from bottom.

Of course would be good to have something generic that can be adjusted.

Of course I don't know source code but instead of full screen using a part of it seems something trivial to add.

Being a developer myself It would be a pleasure to help if you want.

Thanks

 It seems, from reading various threads, that with a pan/tilt camera (eg. TC40) the ability to blank out a certain zone within the total field of view is paramount to correct operation. In my case a tree on the RH periphery of the entire field of view, will often, when windy, grab and keep the cameras attention and hence prevent it returning to its default position to protect the property. This seems quite a flaw in its ability to motion detect and track when you need it to. Surely it's possible to develop a software strategy to deal with this, so we may specify a region to ignore for motion detection?