If your derived tag definition is not showing a value, the problem may be caused by an unreported error, because Modeler does not report script errors for derivation scripts.
To determine if your script is generating any unreported errors, you can try running a copy of the script as a Menu Command. As a Menu Command, Modeler will report any errors the script has.
To run the script as a Menu Command
1. Create a Script item.
2. Open the Script item's Property Pages, click the Settings tab, and set its Script Type to Menu Command.
3. Type a name for the command, and then click the Script tab.
4. Copy your Derivation Script text to the text box on the Script tab.
5. Change the script to write to the Output pane (DisplayOutputWindowMessage "<text>").
6. On the Items tab, make the Script valid for the item type you want to test it with. For example, Class.
7. Create a valid item type, and run the menu command you created.
If the script has errors, those errors will now be reported.
For more information about debugging a script, click
here.