Resize screen problems on large monitors

Has anyone had this issue before, say I have a movieclip called options, and want it to always stay down in bottom right corner, simple, in the resize event
just update the sreen size available and reset the x and y of options accordinging, with whatever offsets needed.

BUT… this is getting thrown off on very large monitors, anything over 27in, sometimes the same code works, sometimes it doesn’t, any help?

anyone come across this before?

thanks

Ikonik