Hide Selection

To hide the Plop-Render selection but still use it, click the triangle icon beside the Render controls and choose Hide Selection from the menu.

The frame around the selection will disappear but the selection can still be rendered without rendering the entire scene.

Click on the Clear and Render button or on the Resume Render button in the Render controls:

Do not click on the Render All button (large center one) as that will disable the Plop-Render and render the entire scene.