You can access the 'Select Exclusive Window Drag & Drop' through the 'Toolbar'.

To  select a window in exclusive mode from your desktop all you have to do is drag the green 'Find Exclusive Window' icon from the 'Toolbar' and drop it over the window you want to be select.

When you select a window in exclusive mode you can have other windows in front of it, or even minimize it, and ScreenCamera will continue to show that window. IMPORTANT: When a window is selected in exclusive mode the refreshing of that window may not work properly.