Ken, thanks for replying, and the the clarification of the functionality.there are now different ways of using focus in auto and manual that will dictate how you use it and what you can lock on the camera settings. In Auto Focus, you will tap the screen to focus while in Manual Focus you will use the slider that appears at the bottom of the screen.
Attached is a table and some images that show the different configurations of Exposure/Focus settings and how you can lock those settings in.
However, the issue is that the Manual Focus slider is intermittently not appearing when Manual Focus is selected, as seen at the end of the video link in post #19 above. It appears properly, by toggling back and forth between Auto and Manual focus modes, until it doesn't at the end. It definitely appears to be a bug in the Explorer app when using the EVO 2 Pro Manual Focus mode. Can you confirm the issue?