I have a panel on the left side of my monitor. That panel only contains CPU, memory usage and network activity graphs. Because of that, I made that panel 1. rather wide and 2. set it to auto-hide because I really only want to see it when I move my mouse to the left edge of the screen and at no other time.

But here's a few somewhat annoying problems:
* This panel isn't hidden when I login half the time, and it remains visible forever unless I move my mouse to the left edge of my monitor and then back again.
* Sometimes the said panel will remain visible even after I move my mouse away from it
* Launching ksnapshot unhides the panel. The panel doesn't show on the first screenshot, though, but the panel remains unhidden forever unless I touch the left edge of my monitor with the mouse.
* Pressing 'take a new snapshot' button also unhides the panel in the same manner launching ksnapshot does.

I'm using plasma5 and don't remember having this issue on KDE 4.

Bonus question: widgets. Why aren't they as tall as they could be?

That's CPU (only showing total load), RAM and network graphs. Each graph could be as tall as the wls1 graph (which is as tall due to a glitch, there would be no graph for ethernet).