The "showFieldMsg()" method does not display messages for Label type fields in Service Portal.
Steps to Reproduce
1. Create a label variable on a catalog item.
2. Create an onLoad() catalog client script for the new item with the code:
g_form.showFieldMsg('YOUR_VARIABLE_NAME', 'test message!!!, 'error',true);
3. Navigate to the catalog item in Service Portal.
Observe the message does not display.
This is expected behaviour in the current Service Portal design. This issue has been identified as a possible future product enhancement. As a workaround, reference the last variable under the label one in the showFieldMsg() method, rather than the label variable itself.
Related Problem: PRB1247434