As a data provider I want to select more than one instrument type

[svietgen]

In the third survey wave of gsl2012, a standardized paper questionnaire and an online questionnaire were used as survey instruments. But I can only select one type. Can we implement a multiple selection?

For now I add an annotation on the instrument detail page to clarify this.

[AndyDaniel1]

I think the solution would be to create multiple (2) instruments and assign them to same survey