Merge pull request #440 from Vocaluxe/AllSongsChallenge_RandomSongFix

All Songs Challenge - Select random song for next round

PartyModes/PartyModeChallenge/CPartyModeChallenge.cs

@@ -427,6 +427,7 @@ namespace VocaluxeLib.PartyModes.Challenge
                     _ScreenSongOptions.Sorting.Tabs = CBase.Config.GetTabs();
                     _ScreenSongOptions.Sorting.FilterPlaylistID = -1;
 
+                    _ScreenSongOptions.Selection.SongIndex = -1;
                     _ScreenSongOptions.Selection.CategoryIndex = -1;
                     _ScreenSongOptions.Selection.CategoryChangeAllowed = true;
                     break;
@@ -718,4 +719,4 @@ namespace VocaluxeLib.PartyModes.Challenge
             return result;
         }
     }
-}
+}