R GUI question

Look at Rcmdr as the base for your additional menu functions.
I am using it for my introductory courses and have added my own menu items.

From CRAN, download and install Rcmdr and read it's documentation.

Also from CRAN you can download and install my addin library RcmdrPlugin.HH
The latter will show how easy it is to add additional functions to
the Rcmdr menu.

Rich