Why is my screen beeping and automatically selecting things?

This is an issue with power being delivered across two flat molded cable connectors and the small gauge wire in the cable itself. Every time power fluctuates, it is exaggerated at the load (monitor). If I could find which pins on the connector are power and ground. I would add a couple of hundred micro-farad electrolytic capacitor to act as bulk decoupling for power at the load. At some point when I have the time, I’m going to track down a power and ground point on the monitor, I’ll verify the results. A couple of high frequency decoupling caps might be in order as well.

The consequence of using a flat molded cable.

The display board on my ender 3 started getting random clicks. My thought is that this is a grounding issue with the display board. I tried resting my hand on a screw head on the ender 3 frame and one of the screws that hold the display board in place(no cover) and the problem went away until a removed my hand. Next I tightened the hex screws that hold the display bracket to the ender 3 frame and this seems to have cleared up the problem. My next step will be to ground the display board to the frame with a dedicated wire.

What I believe to be true is the display needs to be grounded to the frame. This is currently accomplished though the bracket, and associated screws, that hold the display to the frame. Not really an ideal arrangement.

When that happens on my computer or anything else I have it is usually a stuck switch - or I am leaning on my keyboard. try activating any switches on the display or a kbd to see if any are stuck