I have a multitrack composition. I want to add a number of bars to only one track but GuitarPro insists on creating the bars in ALL of the tracks. I've tried creating content and then pasting that into the track but that doesn't work either. What am I missing ?
Yes, it's the nature of such programs that every instrument has the same number of bars.
I don't think Guitar Pro has a 'ripple edit' function. So you'll need to shift the data in one track along by one bar length manually.
Select that track from the point where you want to insert a bar until the end of the piece. Use the Single Track Cut function to cut the content to the clipboard. Paste it in one bar later.