Questions re Dependent Enumerations

I have been following the examples for customizing attributes in RTC 3.0 but have come up against some problems.

Q1:
I have the simple case of one enumeration controlling what options occur in another. However, in the example provided, if The OS chosen is "Windows XP" and an IE browser is selected, when the OS is changed to "OS X", where an IE browser is not applicable, this option remains selected in the list until an alternative is chosen. BUT no error or warning is made against the attribute, so the workitem could be saved in an inconsistent/error state. Is there any way to cause an error to be raised so that the work item cannot be saved until the inconsistency is corrected?

Q2:
Having got the two enumerations depending on each other, how can I get this same effect for multi-select checkboxes based on enumerations?
An example user story would be product X has versions 1.0, 1.1 and 2.0 in service. Each version has a list of platforms on which it is supported: X1.0 on Windows & AIX, X1.1 on Windows, AIX and Linux 32bit and X2.0 on Windows, AIX, Linux 64bit and z/OS. A defect is found in X1.0 and X1.1. Having selected which (multiple) releases are affected, I only want the applicable platforms that are possible options to be able to be selected (ie to indicate if the defect's scope is only for certain platforms within those versions). In the above scenario I would want the Linux 64bit and z/OS platforms to be greyed out (unable to be selected) as X2.0 is not affected by the defect.

Any thoughts?
Rachel

Re Q1: This is tracked in https://jazz.net/jazz/resource/itemName/com.ibm.team.workitem.WorkItem/123579

Re Q2: It could be that the multi-select presentation doesn't participate properly in the update process. I would suggest to create a work item for this.