how to control the number of characters shown from a popupmenu

Hi,

I have a popupmenu1 control, where I have two choices: us/m and us/feet. I want to get the selected option by using the following code:

MDunit1=get(handles.popupmenu1,'String');
idx1=get(handles.popupmenu1,'Value');
selectedMDunit1 = MDunit1(idx1);

However, the selected unit 'selectedMDunit1' only shows the first character, so I do not know if that corresponds to first or second option since both starts with the same letter. I was wondering if there is a way to show at least 4 characters to differentiat the two of them. How can I do this?

Thanks