Scenario 1)

- Set MultiSelect1.Enabled=false; 
- Do a postback;

Expected: MultiSelect remain disabled
Actual: MultiSelect gets enabled

Workaround: set MultiSelect1.Enable = false instead of .Enabled.

Scenario 2)

- Add a MultiSelect inside asp:Panel
- Disable the asp:Panel

Expected: MultiSelect is disabled
Actual: MultiSelect remains enabled