FlashDevelop debugger window showing incorrect resolution

I have an AIR Projector game that's set to 640x640 resolution in the Project -> Properties -> Dimensions field. But for some reason when I debug the game the window sizes itself to 800x800.

Here's the properties window.

And here's what happens when I launch the game.

You can see the image is 800x800. It should be 640x640, I don't know why it's being scaled up by 25%. This stretches the image and makes the quality worse.

I already found a hack-y solution but I was hoping there was a more elegant reason or solution as to why this is happening.

I have to go into the AIR Application Properties and set the Initial Window Size field to 526x549, as shown here.

When I set those fields to those values (keeping in mind the Project Properties Dimensions field is still set to 640x640), the game then launches in the correct dimension with perfect image quality.

I found this other user having the exact same problem. Their solution was to scale the main Sprite to fit the stage dimensions, but I'm trying to avoid scaling to preserve the image quality.

I'm coming back to this because the realization just hit me while going through my computer settings. The reason the game was being rendered 25% larger is because my 1440p monitor is set to 125% scale in my Windows 10 display settings.