Call outs. In the Properties panel click on the force icon. To use a call out you can add it to a clip for the specific duration you wish to appear. You can move it and modified size, just like in the video properties clip. Now you can choose what to highlight the mouse cursor the foreground window. Yes, ScreenFlow identifies the front window, or the freehand which lets you decide what to highlight.

Then you can modify the opacity of the other part of the screen you can blur inside the highlight or blurred the background by checking that option. You can zoom the highlight section or increase the highlight space by increasing the border. You can modify the outline border at the shadow, federate a bit and adjust the building in and out of the highlight.