Hi, I am trying to create a form where there are two select menus, both using dynamic_options, where one is the parent menu that is chosen first and based on the selection(s) there is a refresh and the second menu gets populated based on the first menu's choice(s). <param name="names" type="select" multiple="true" optional="true" dynamic_options="dyn_options('names')" refresh_on_change="true" label="Filter By Names"/> <param name="values" type="select" multiple="true" optional="true" dynamic_options="dyn_options('values', $names)" label="Filter by Values" /> There seems to be a problem when the form loads for the first time as $names is not selected yet. I get a syntax error like "Invalid string", when I remove $names as a parameters from my second dynamic_options function call everything is fine. Does someone know how to achieve the functionality I'm aiming for in Galaxy without having to use the deprecated <pages> tags? Is there a way in Cheetah to set a default value for $names and if so how would I do this in the tool xml? regards, Leandro