A relationship a grid and a popup windows

Fristly, I load a data in a grid. And dubble click a row of grid then popup a window to show this row record.

I use the tab move in the popup window form but I move to the backgroup’s grid row cell.

I want to ask I can set focus only on the popup windows and not movet o the backgroup’s grid row cell ?

How about this !

Can you add some graphic with desirable result to clarify the expected behavior?