TMVAGUI interface

Dear all,
I am new to ROOT.
I have created an output root file after the BDT. I can see all the variables in the output root file, which I used in the BDT method. But When I am going to see them using TMVAGUI , I can not see all the 19 variables. I can only see 6 variables. Can anyone please suggest me something so that I can see all the variables? Thanks!
I am using the following macro:

void testnew(){

        TString         dataset = "datasetOSSF04Feb_MET_2017";
        TString         dirName = "InputVariables_Id";
        TString         title = "TMVA Input Variables";


I am not sure how it is supposed to work. I tried it on some root files I have. One contains 11 items for instance. I see all of them. But I see it generates a collection of buttons, not a list. So I guess that will limit the number of items. @moneta can tell you more I guess.

Which function of the GUI are you using exactly ?

Many thanks @couet and @moneta !

The problem has been resolved. There was some problem with the root file. Now I can see the 19 variables.
Thanks again!