To use the text string coming from the popup options, turn off the "evaluate" checkbox as shown below. This allows comparison of text in the option in the initialization. There is code snippet below
if strcmpi(Parameter1, 'option 1')
% Do this
% Do something else
The above code snippet only works if "Evaluate" checkbox is unchecked. Otherwise in the initialization, Parameter1 is an integer corresponding to which option was selected in the popup of Parameter1. For instance with the "Evaluate" checkbox checked, if the first option in the popup was selected, Parameter1 is 1 and if the second option was selected, then Parameter1 is 2.