Workspace keeps moving when I'm zoomed in to an area of the pasteboard in InDesign!!!!!

Hi there - Ok, so I'm working away in InDesign and zooming in on an area and just about to edit a line or text or path or whatever and suddenly the pasteboard/artboard or whatever you call it just flies off to the left or up or down or right for no reason that I can think of as being useful to me at all and it's driving bonkers!! Any ideas anyone?

Cheers

Jonathan