Hi Colin,
You definitely have NO scrollbars on the form, correct? If so, blow them away as a test. If not, then have you also ruled out inheritance issues on the form itself?

What about the scalemode in tools, options? Does it match the scalemode on the form properties?

Is this a subclassed form by any chance? What about the controls on the form and the title bar settings? What about max design area settings in tools, options? (Going through everything here no matter how redundant). Is your Arial font a TTF? If not, change it. Also, what about any maxwidth and maxheight settings in the form properties and anyplace else in your environment? Any settings in the config.fp for _screen ? Are you using the same size of font everywhere on the form?