Unresponsive script warning with Firefox browser

When opening the Workload Designer with Firefox, the following warning message might appear: 
Warning: Unresponsive script 	
A script on this page may be busy, or it may have stopped responding. 
You can stop the script now, or you can continue to see if the script will complete.

Cause and solution:

This is caused by a Firefox timeout. If prompted with this warning message, select the Continue option.

This behavior of Firefox is ruled by its dom.max_script_run_time preference, which determines the timeout that the browser must wait for before issuing the warning. The default value is 10 seconds, and might be changed to another value according to your needs.

To change this value, perform the following steps:
  1. Type about:config in the address field of the browser.
  2. Scroll down to the preference, select it, change the value, and click OK.