PDF architect is bigger than screen size

Help!

I've just downloaded PDF Architect for my Windows tablet and the right hand side of the programme appears to be off the right hand side off the screen. The close box (X) at the top right is off the screen and the right hand side of the open PDF document is also off screen.

I don't have this issue with other software so it's not a general display issue with the tablet.

What can I do to resolve it?