Custom Popup Applet in Siebel Returns Error: "Method ShowPopup is not allowed here (SBL-UIF-00348)"

Background:

A custom button was created with the method name 'abc', which triggers a workflow through a Business Component user property.
This workflow is designed to open a popup applet that displays a BI Publisher (BIP) report.

However, when clicking the button, although the popup applet opens, it displays the following error message inside:

Method ShowPopup is not allowed here (SBL-UIF-00348)

 

Error Message:

We detected an error which may have occurred for one or more of the following reasons:
Method ShowPopup is not allowed here (SBL-UIF-00348)

Debug and Resolution:

After reviewing the Siebel Personalization Log, it was observed that following the execution of the custom method 'abc', Siebel internally calls the 'ShowPopup' method.

It turned out that 'ShowPopup' was also being used for another popup applet where it had been explicitly disabled via an Applet User Property (CanInvoke = FALSE).

For testing purposes, we deactivated that specific user property, and the popup started working as expected without the error.