How to Disable "Spaces"???

Hold down the control - up arrow key and enter Mission Control . Then go to the top menu where the Spaces are Click and hold down on the Space until an X appears in the top left corner. Repeat as required until you have 1 Space. Hit control - up arrow again.

Hey, Eric, many thanks for your help. I followed your guidance. The final trick at least for me after following your instructions was closing out Safari and Mail both and starting them again. Problem is gone. I realize "Spaces" could be a help but in my case, with dual displays, not necessary and a hinderance. As an aside I also entered a chat with Apple about the problems I was having. To my astonishment the first support person I reached said that he or she had never heard of the concept, "Spaces." I'm still amazed. I sent them a link to one of Apple's pages explaining the idea. So . . . doubly glad you were there to help. Many, many thanks, Christopher

The proposed solution did not work for me. I hate the spaces jumping around. But followed all the suggested unchecking of boxes and still spaces jumps around. Do I need to restart or something like that?

Thank you for your help. I found my way to Mission Control. We need to go a bit slower for me. I don't understand what you mean by "top menu." I don't know where the Spaces are. Here's the window I found when I went to Mission Control via System Preferences. Also for the record when I pressed control and the up arrow key that did not take me to Mission Control. As you can tell, I need additional assistance please. Many thanks, Christopher

You can assign applications to open in specific desktops & add or delete any spaces,

Follow the link :

OS X El Capitan: Work in multiple spaces

1. Go to: Apple > System Preferences > Mission Control and uncheck all of the boxes that pertain to Spaces.

2. Go to: Apple > System Preferences > Keyboard > Shortcuts > Mission Control and uncheck any unwanted keyboard shortcuts.

At the bottom, the top box on the left labeled Mission Control, click on that and from the dropdown menu select ^ up arrow. Then try what I posted earlier.