Remove One Pixel Border on Windows 11

I have an annoying one pixel border around all windows that shows my background. This is NOT fixed by disabling the "Show accent color on title bars and window borders". I have included a screenshot where you can see the one pixel border. Is there anyway to disable this one pixel border of separation?

this defect does not appear here, these are the windows side by side correct?
Whitout color border

with blue color border

yes there does not seem to be any defect in your two screenshots. I have included a second screenshot where I do have the "Show accent color on title bars and window borders" enabled (blue) and you can still see a few pixels of my wallpaper background showing as well as the blue border

bump?

I'm sorry but I do not see the problem. It is normal for all windows to have a 1 px border. If you do not choose a color Windows automatically chooses one for you and picks one of the colors of your background. It's up to you to choose another color. I think what you see that you think is your background is the border color that windows picked out of your background since you did not choose a color yourself.

As you can see by my first screenshot I have 3 windows open. The active window border (a maroon color in Weather app) is the same accent color I chose in settings. The turquoise color is my inactive border color. Before I changed it it was a grayish color. When I snap the 3 windows I do not see any of my background.

I will say that before I snapped the windows, none of them was opened full screen. I have found that setting the properties of a program to open full screen can cause certain issues. Instead, the first time I open a program I drag the edges of the window to be almost full screen. Windows then remembers the size and makes it permanent unless I drag the edges again to re-size it.

With a third party tool Winaerotweaker you can change the width of the borders and the inactive title bar colors.(See second and third screenshot)

The problem isn't the 1 px border, the problem is that there's a 1 px border of the wallpaper showing. I expect/want there to be a solid blue border around my windows with NO background showing (like in your first screenshot).

Even with a 10 pixel border width using winaero it interesting still has the same behavior and shows one pixel of my wallpaper???

Another thing I want to note is that in my screenshot below, you can clearly see that my selected border color is BLUE, with the selected window on the left, but there is still a 1 px of my wallpaper showing.

Have you tried turning off all 3rd party customisation to see if maybe that is the cause?