DRR 'default refresh rate' setting can be enabled without setting a value from the dropdown menu.

h4. Steps to Reproduce
1. Open Config
2. Enable Dynamic Refresh Rate
3. Enable 'default refresh rate' but do NOT set a value
4. Close Config

// ShowStopper //
In MP GUI Setting :
1. Reset default DRR Setting.
2. Try to add or set something and MP Crash.


h4. Additional Information
We should add a check that default refresh rate value should be set prior to closing config.