KB204840 : When trying to set Custom Display Forms or Sorting on selectors in MicroStrategy Web 9.4.1, no popup window is displayed if the Web Administration setting “Session information is included on the URL” is cleared.

SYMPTOM
In Strategy Web 9.4.1, there are selector settings that enable developers to set the Custom Display Forms and Sorting on selectors. 
1)  Create a document with any grid as dataset in Strategy 9.4.1 Web
2)  Create a drop down attribute element selector
3)  Right click the selector, choose Properties and Formatting > Selector and change the dropdown for "Displayed forms" to "Custom..." and note that nothing happens - no popup window comes up.  The same issue occurs when clicking the sorting button.
However, users may notice that that this issue will only occur if the Web Administration setting called Session information is included on the URL is cleared.  This setting can be found by accessing the Web Administration page and clicking the Security link on the left side of the page.  If this setting is enabled, then there will be no issue.
 
CAUSE
This is a known issue with Strategy Web 9.4.1.
ACTION
Contact Strategy Technical Support for an update on this known issue.
 
WORKAROUND
Enable the setting Session information is included on the URL on the Web Administration Security page.