I think this is related to MTX but it appears randomly... any ideas?

 

I've got the SDK installed maybe it's a debug mode or something?

 

I've seen this happen on occasion, but I can't pin it down to any one cause. I usually shut FSX down, re-boot my computer, and re-start FSX, and the issue disappears.

 

Wish I could be more helpful, Ryan ...

Now that you mention I've had it happen to me once before too. I just ignored it and it didn't happen again so I forgot all about it. Hopefully yours will disappear too even if you can't find out what it is.

I also get something similar, but always with the AI aircraft being listed instead of the nearest RWYs. I always ignore this, as I usually have the menu bar hidden, and all important options are listed as usual.