I am able to create a test case in 'TUI' but when I try the same in the GUI tool the only field that I can't enter or pick from is the Parameter 'Type' pull-down list. This is my first try. The Name, Is-Null, InOut, and Value both permit entry or offer a pick list.
Am I doing something wrong or is this an issue with Oracle?
Just fyi, the GUI tool was my attempt to do a bit of GUI programming with Java. It works for the simplest cases only. So it may very well be broken for the case you mention.