Don't throw from properties used in databinding.

The BooleanCodeStyleOptionViewModel are a glue between older checkbox
style options and the new grid UI with severity levels. Well, the older
options don't have severity levels and I was throwing NotSupportedEx,
but forgot they were used in databinding. As a result we had non-fatal
exceptions. This change removes them.

src/VisualStudio/Core/Impl/Options/AbstractCodeStyleOptionViewModel.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System.Collections.Generic;
+using System.Linq;
 using Microsoft.CodeAnalysis.CodeStyle;
 using Microsoft.CodeAnalysis.Options;
 using Microsoft.VisualStudio.Imaging;
@@ -32,12 +33,16 @@ internal abstract class AbstractCodeStyleOptionViewModel : AbstractNotifyPropert
         public double DescriptionMargin { get; set; }
         public string GroupName { get; set; }
         public abstract CodeStylePreference SelectedPreference { get; set; }
-        public abstract NotificationOptionViewModel SelectedNotificationPreference { get; set; }
         public List<CodeStylePreference> Preferences { get; set; }
         public List<NotificationOptionViewModel> NotificationPreferences { get; set; }
         public abstract bool NotificationsAvailable { get; }
 
         public virtual string GetPreview() => SelectedPreference.IsChecked ? _truePreview : _falsePreview;
+        public virtual NotificationOptionViewModel SelectedNotificationPreference
+        {
+            get { return NotificationPreferences.First(); }
+            set { }
+        }
 
         public AbstractCodeStyleOptionViewModel(
             IOption option,

src/VisualStudio/Core/Impl/Options/BooleanCodeStyleOptionViewModel.cs

@@ -39,19 +39,6 @@ internal class BooleanCodeStyleOptionViewModel : AbstractCodeStyleOptionViewMode
         }
 
         public override bool NotificationsAvailable => false;
-        public override NotificationOptionViewModel SelectedNotificationPreference
-        {
-            // presently, these options do not support notification styles.
-            get
-            {
-                throw new NotSupportedException();
-            }
-
-            set
-            {
-                throw new NotSupportedException();
-            }
-        }
 
         private CodeStylePreference _selectedPreference;
         public override CodeStylePreference SelectedPreference