Figure, linkdata, and GUIDE made GUI: how to share workspace

I have made a GUI which creates different figures with Figure(NNN) command. I wanted to link data present in different Figures and calculated, reformatted, etc. in GUI using different buttons. So I used "linkdata" command with aproppriate XDataSource and YDataSource properties. I always got failed link.

The only solution (or better to say bypass) was if I have put the variables to link into a global structure and while I am in command widow issue the command 'global xxx' where xxx the structure containing the linked data. So I have put this global variable also into the workspace of the command window. In this case everything was working well, the linked data were updated etc.

But this is only a bypass, I would like to run the program from an exe file and without even having Matlab command window.

What I am making wrong?

Thanks,

Csaba