I am using as source 'Windows Capture' and am trying to record a live screen presentation which is running using Firefox. All appears to be in order when I begin recording. Afterwards when I check the entire 3 or 4 hour presentation I find that after an inital 3 or 4 minutes the capture or recording which OBS has recorded is showing the full screen but it is only around 20% of my screen. It looks like a sort of PIP feature. Anybody able to help?