Fullscreen mode doesn't "fit to screen"

Pretty much.

I'm massively oversimplifying this and this wouldn't be applicable to the zoom feature, but Balsamiq is a Flex app sitting in an AIR wrapper. Is that right?
All in all its just lots of flash. In the case of the full screen mode, could you not just resize the wrapper that the mock-up is sitting in to the screen size? There's a whole bunch of maths involved to handle the 16:9 vs 4:3 resolutions which is a pain, but is possible.

lol... version 6! So you're telling me you can fix this for my demo tomorrow!!?? ;oD

It would definitely be good to see this in there, so that you can do a demo on a client site without worrying that their weird and wonderful huge plasma screen at some bizarre resolution or old school 800x600 max resolution projector will destroy your incredible mockups. :)

Similarly, I would like to be able to use my full desktop (which spans two monitors) in presentation mode, which I can't currently do, even without zoom capabilities. Mockups picks one monitor or the other to use (not sure how it chooses, maybe based on where *most* of the application window sits?)

I've ran into the same issue, creating Mockups at 1920x1200 and then using an infocus projector that does 1024x768. I'm using the desktop edition, so I'm not sure if it works in the web version, but what I've tended to do was copy to clipboard and past in powerpoint, then shrinking the image to fit. Granted, you don't get to modify the mockup while displaying, but it does deal with the fit to screen issue.

One suggestion I would have if/when a feature like this is implemented. Using Excel terminology, allow the ability to set a "Print Area". There are a number of mockups that I have done that I will slide pieces over to the right that I am not using at the moment but I don't want to delete. When adjusting the zoom size I wouldn't want to see these at full screen. The other consideration is scrolling up and down. If the size of my print area doesn't match the ratio of the monitor, I would need the ability to scroll up and down. This comes into play with mockups of web pages. (When pasting to powerpoint I've had to crop images to multiple slides)