Try this: pop out the gauge, put it on the screen you want it on, and maximise it. You’ll still have the title bar visible and black bars to left and right (assuming the screen is the same aspect ratio as the gauge, so for G1000 it’s 4:3, and for G3000 it’s 16:10; the Garmin displays are not 16:9, so the pop-out is 16:10 and you will have some side bars to fit it on a 16:9 screen correctly).
Then, with the pop-out focussed, hit ALT+ENTER. The pop-out will go full-screen, removing the title bar. What I’ve found is that sometimes the sim calculates the size of the content using the true aspect ratio of the pop-out, but uses the pixel height of the pop-out window including the title bar when it works out the width of the content, even if the title bar isn’t visible, which causes exactly this black-bars-on-either-side problem.
Now, I appreciate you’re talking about fitting pop-outs inside Air Manager bezels, but the problem is the same. The gauge aspect ratio calculation doesn’t include the title bar, but the title bar is added to the number used for the width calculation, so you get the unwanted black bars. POPM’s ‘remove title bar’ functionality works, but the sim still draws the gauge as if the title bar was there and so the aspect ratio is still off.
For AM use, what I do is use POPM and, when initially setting it up, I size the pop-out to be smaller than the hole in the bezel, and position it in the middle of that space. I leave the title bar visible (always). Then I use the window movement and sizing keys in POPM to move the pop-out to the top left corner of the hole and I keep going up until the title bar disappears behind the bezel. You need the AM bezel panel set to ‘always on top’ for this to work. Then I expand the pop-out until it fills the hole. Doing this, I can get the correct aspect ratio. Then, if you wanted to, you could stop using POPM because the pop-outs will return to where you put them next time; but I will always use POPM to avoid having to pop anything out manually.
EDIT: I’m not sure I’m explaining this very well. What’s key to understand is that the aspect ratio of the window content will be correct (no black bars) only if the overall pop-out window size is in the correct aspect ratio adding the additional height for the title bar. You can always size a pop-out with the title bar on to remove black bars from the content area. By having the AM bezel set to always on top, you can do this and hide the title bar behind the bezel, while maintaining the correct aspect ratio for the window content, since the holes in the AM bezels are of the correct aspect ratio too.
