Hi Illona,

the only option I see is to write your own work item save advisor. You will have to use the built in advisors in addition to your own advisor if you want to have UI support to show which attributes are required (the asterisk) and in that context you will have to live with whatever hover is provided by the built in stuff.

The reason is quite complex and not obvious. I wrote about this in https://rsjazz.wordpress.com/2015/06/19/a-custom-condition-to-make-attributes-required-or-read-only-by-role/ section How Does the RTC Code Work?

What happens is that RTC provides an extension point to prevent saving when attributes are required etc. The extension works if you press the save button. To show the user that something is required or make it read only etc. the UI needs to compute this before the save button is pressed. To allow for that there is a hardcoded relationship built into the UI code working with the configuration of the built in advisors to show the information.

It is impossible to hook up custom advisors here. That is why you can not make any impact on the UI. You can only show specific errors when the user presses the save button.