Fix blank screen issue

Also fix some other bugs and improvements (easier party modes, volume fixes, new fields for screens to control volume and popups)

VocaluxeLib/Menu/CMenu.cs

@@ -112,11 +112,6 @@ namespace VocaluxeLib.Menu
             _ThemeScreenSettings = null;
         }
 
-        protected static void _FadeTo(EScreens nextScreen)
-        {
-            CBase.Graphics.FadeTo(nextScreen);
-        }
-
         #region ThemeHandler
         protected override void _ClearElements()
         {
@@ -569,6 +564,11 @@ namespace VocaluxeLib.Menu
             get { return CBase.Settings.GetRenderRect(); }
         }
 
+        public virtual EMusicType CurrentMusicType
+        {
+            get { return EMusicType.Background; }
+        }
+
         protected void _ResumeBG()
         {
             foreach (CBackground bg in _Backgrounds)