Expanding the GUI capabilities of Matlab's user-interface is possible with undocumented and unsupported methods. But it is likely, that different methods are needed for different Matlab versions. Therefore the next update would make all your work useless or could even cause severe bugs.
It seems to be more promising, if you create a dedicated function, which evaluates code, which is copied into the clipboard. The needs 2 or 3 additional mouse clicks, but does not depend on the Matlab version.