Hello. I have provided the steps below that will walk you through the process of setting up custom drop down lists in the Defects module that will meet your needs.
Click Tools --> Customize --> go into the 'Workflow' module --> Script Generator - List Customization for Defects Module --> In the Script Generator - List Customization window, you will create the statement ''When primary (Click the hyperlink and select 'Root Cause Category') value is changed, (Click the ,'s hyperlink and select 'Root Cause Code) selection list will change''.
In the section below, you will see that the first line states ''For primary field value Import, use list for secondary field''. Which ever rule/line has the value ''Import'' displayed in it, you will need to click the hyperlink and select from the menu that displays. The 'Project Lists' window will display where you will first name the list ('Pivot Tracker List' for example). Next you will need to click 'New Item', enter 'Pivotal Tracker' into the 'Item Name' field and click 'OK'. Once you have completed your drop down list, click the 'OK' button. Back in the 'Script Generator' window, you will need to click the hyperlink for any remaining rules/lines and select the value 'Root Cause Code' from the menu. After you have populated each of the rules in the lower section, you will then click 'Apply Script Change' --> Click 'Return' --> Select the 'Major Change' option and click 'OK'.
Back in the Defects module, when the 'Root Cause Category' field is populated with the value ''Import'', the only value that should be available in the 'Root Casue Code' drop down will be ''Pivotal Tracker''.