Re: edit grub in graphical mode...
I think such a thing exists (Grub Customizer, maybe but you should be aware of something.
When you introduce anything to a boot process you increase the risk of future boot failures. The booting process is like a chain with link after link. This chain can easily be broken. Any change made today may have no detrimental effect until you run an update 3 months down the line. Then you don't know where to look!
What is it that you want to do, exactly?
Sony Vaio AR51SU
Nvidia 8600M GT