Windows allows you to use multiple displays at once. You can either duplicate, extend, or use one of them as your stand alone monitor. In all of these cases you’ll need to select a main display.
The only exception is the duplicate option. I’ll come to that shortly. First, the role of the main display must be explained.
What is The Main Display?
When there are multiple monitors connected in one computer, the main one is the control center of them.
If you open an application from a secondary monitor, that application will come up on the main monitor instead of the one that you tried to open it in.
After you open an application on the main display, you can then transfer it on one of your secondary displays. In overall, the main display is the center of all your displays.
If you choose to extend your displays, or make one of them your standalone monitor, a main display will have to get selected. However, that’s not the case with duplicating.
Duplicating simply makes all of the displays the main display. So, if all of them are the main display, then none of them are.
Something To Keep in Mind
When using multiple displays, only one aspect ratio can be used. Which means that if you have two monitors with a different aspect ratio, one of them will look stretched or have black borders on the sides.
For example, I have two displays. The first one has an aspect ratio of 16:9. and the other is at 4:3. When I use them at the same time, the first one has block borders on its sides unless I choose to stretch the image.
Setting A Main Display
First of all, open the display settings. To do that, right click on your desktop, and select display settings.
The next thing that you’ll have to do, is to identify which display is which. The easiest way to do that, is to duplicate them first.
Scroll down where there is an option called multiple displays, click on it, and select duplicate these displays.
Then scroll up and click on identify. A number will pop up on each monitor that you have, the same numbers can be found on the top of the display settings. These numbers represent the monitors.
Now that you know which monitor you’re looking for, scroll down again on multiple displays and choose extend these displays.
Then scroll up again and click on the number that represents the monitor of your choice.
Only after you’ve made sure that the right monitor is selected, scroll down to multiple displays again. Right below it, there should be the option to make the display of your choice the main display.
Click on it. Now that display should be your main display.