I have added FastFilterFields to a grid, and by default displays at the bottom of the grid, and I need to move it to the top. Any help or suggestion is greatly appreciated. 
I have looked at the Layout Properties of the grid, but have not been able to find the answer.
Utilzing the PXGrid controls SkinID="PrimaryInquire" coupled with setting the FastFilterFields="Field1, Field2, Ect" would bring the search control from below the grid as can be seen on screen AP401000.
That being said It would be more appropriate to modify your design to follow Acumatica methodology.
CS211000 as example.CS-ReasonCode as example.