move FORCEFILESYSTEM into Initialize

Author: miloush

src/Microsoft.DotNet.Wpf/src/PresentationFramework/Microsoft/Win32/CommonItemDialog.cs

@@ -428,8 +428,7 @@ private protected virtual void PrepareDialog(IFileDialog dialog)
             dialog.SetTitle(Title);
             dialog.SetFileName(CriticalItemName);
 
-            // Only accept physically backed locations.
-            FOS options = _dialogOptions.Value | FOS.FORCEFILESYSTEM;
+            FOS options = _dialogOptions.Value;
             dialog.SetOptions(options);
 
             IList<FileDialogCustomPlace> places = CustomPlaces;
@@ -563,6 +562,9 @@ private void Initialize()
             // - Force no mini mode for the SaveFileDialog.
             SetOption(FOS.DEFAULTNOMINIMODE, true);
 
+            // Only accept physically backed locations.
+            SetOption(FOS.FORCEFILESYSTEM, true);
+
             //
             // Initialize additional properties
             //