preventing checking out remote branch in gitk

Hello,

I have a fair number of new users, mostly refugees from VSS and SVN, and they do use the GUIs a fair bit.

And they keep doing this :-) I know what you're thinking: teach them not to do it...

But doing this at the command line gives you a nice warning, and a GUI is (like it or not) considered more "safe" (aka less powerful). So it should go one better and just refuse :-)

Is there any way we can disable "Checkout this branch" for branches that are not local in gitk? I'm willing to play around with the code and test it if someone can give me a couple of pointers at least.

Thanks,

Sitaram