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.
One Exception in Changing Main Display
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.
Sometimes the second display is not detected by the system, under Multiple displays click on Detect, to detect the other display manually.
After detection, you would see this in your Display Settings.
Now scroll down and under Multiple Displays, select Extend these displays option
Keep this Settings
Now under Rearrange Your Display, you will have the option to select the displays. Select the display which you want to set as Main Display
Scroll down again and under Multiple Displays, click Make this my main display box
Change the Main Display: FAQs
If you find “Make this my main display” option is grayed out, then it means that the currently selected display is already set as the main display.
You can change the primary display number from the settings and then under Rearrange Your Display, select the number of display you want to set as primary.