I have been a Mac user since 2012. My issue is that even with dock hiding set to off, the dock hides itself until you click on the right screen where its hiding (when using multiple monitors)
I use three monitors currently side by side. I would like the dock to be in the middle monitor on the bottom of screen
however, 'bottom' alignment will case the dock to switch to any of the three monitors, depending on which one i currently clicked on an app in last. This is extremely bothersome, because i always look to the middle screen at the of the bottom of the screen to use the dock. But sometimes its gone, and i have to mouse around left or right monitors to find out where it is.
The only way to get thge dock to stay put on the same monitor, is to set 'lef' or 'right'
but that means my main dock is to the far right of the right hand screen or to the far left of the left hand screen. It makes no sense to have to 'crick my neck' to the fatrthest point left or right of my desk to control my apps from the dock. But its impossible to set the dock to stay in the middle.
This is one of a few issues which Apple haven't worked on and don't seem to have any intention of working on. This is terrible for people who wqork with multiple screens. Its in my top missing features list in OSX (the other one being a way to default text font size in a new mail on the mail app, which always has tiny tiny text, and on a 4 k screen needs a microscope to read)