Variable range in web interface

Hi,

I tried to use the variable range in my web application, I define the vairable's apperance as helpinput.after I lunch the web application,when I get the popup selction list window, the top part is "value selection", at this time the "TO" selection field is not activate yet, I can only choose single value for the variable, only after I choose [ ] in the vairable's dropdown nemu, the "TO" filed is activated, I can then type in the low value and high value, then I hit enter, all the value between that range is displayed under "value list" part,however I still can only choose single value not the range for my variable. Anybody can help?

Thanks in advance.