Running all the latest downloads and beta... I get garbled text in the window, some characters are clear, others are replaced by 'blocks'...

It sounds like you are using Flight sim's built in viewer not Adv Display. You may just need to turn it on. In Flight Sim please click on the Modules menu item. The second item down should be Adv Display. Please click on it. Adv Display should appear in the top left corner of your screen. From here you can move and size to your liking.