Config JET UI - Single Select Pick Lists : A pure CSS method for rule-based constraints
Currently Single Select Pick Lists in Config can't be the action attribute of a constraint rule. By generating CSS inside a Config HTML attribute wrapped in <style> tags using a Recommendation Rule, you can effectively constrain values dynamically for SSPL's displayed as pull-down menus.
Create a Recommendation Rule to generate the below CSS as required.
The first two CSS rules are static and disable reacting to pointer events of parent elements for each menu item--hover, click, etc.--from a mouse, although they do not prevent other means of navigating lists such as arrow keys.
The third rule alters the appearance of menu items, which are selected using the variable value, so require a CSS selector per value. The example sets opacity of disabled items to 50%, though you could certainly alter this to just about anything CSS supports.