diff --git a/stepmania/src/NoteData.cpp b/stepmania/src/NoteData.cpp
index dd6944a298..b4e8ccfb6f 100644
--- a/stepmania/src/NoteData.cpp
+++ b/stepmania/src/NoteData.cpp
@@ -40,12 +40,29 @@ void NoteData::SetNumTracks( int iNewNumTracks )
 
 
 /* Clear [rowBegin,rowEnd]; that is, including rowEnd. */
-void NoteData::ClearRange( int rowBegin, int rowEnd )
+void NoteData::ClearRangeForTrack( int rowBegin, int rowEnd, int iTrack )
 {
+	/* Optimization: if the range encloses everything, just clear the whole maps. */
+	if( rowBegin == 0 && rowEnd == MAX_NOTE_ROW )
+	{
+		m_TapNotes[iTrack].clear();
+
+		for( int i = GetNumHoldNotes()-1; i >= 0; --i )
+		{
+			HoldNote hn = GetHoldNote(i);
+			if( hn.iTrack != iTrack )
+				continue;
+			this->RemoveHoldNote( i );
+		}
+	}
+
 	/* Crop or split hold notes overlapping the range. */
 	for( int i = GetNumHoldNotes()-1; i >= 0; --i )	// for each HoldNote
 	{
 		HoldNote hn = GetHoldNote(i);
+		if( hn.iTrack != iTrack )
+			continue;
+
 		if( !hn.RangeOverlaps(rowBegin, rowEnd) )
 			continue;
 
@@ -74,11 +91,14 @@ void NoteData::ClearRange( int rowBegin, int rowEnd )
 	}
 
 	/* Clear other notes in the region. */
-	for( int t=0; t<GetNumTracks(); t++ )
-	{
-		FOREACH_NONEMPTY_ROW_IN_TRACK_RANGE( *this, t, r, rowBegin, rowEnd )
-			SetTapNote( t, r, TAP_EMPTY );
-	}
+	FOREACH_NONEMPTY_ROW_IN_TRACK_RANGE( *this, iTrack, r, rowBegin, rowEnd )
+		SetTapNote( iTrack, r, TAP_EMPTY );
+}
+
+void NoteData::ClearRange( int rowBegin, int rowEnd )
+{
+	for( int t=0; t < GetNumTracks(); ++t )
+		ClearRangeForTrack( rowBegin, rowEnd, t );
 }
 
 void NoteData::ClearAll()
diff --git a/stepmania/src/NoteData.h b/stepmania/src/NoteData.h
index 9f7cf6e741..e9ee3b2a65 100644
--- a/stepmania/src/NoteData.h
+++ b/stepmania/src/NoteData.h
@@ -68,6 +68,7 @@ public:
 	void MoveTapNoteTrack( int dest, int src );
 	void SetTapNote( int track, int row, const TapNote& tn );
 	
+	void ClearRangeForTrack( int rowBegin, int rowEnd, int iTrack );
 	void ClearRange( int rowBegin, int rowEnd );
 	void ClearAll();
 	void CopyRange( const NoteData& from, int rowFromBegin, int rowFromEnd, int rowToBegin = 0 );
diff --git a/stepmania/src/NoteDataUtil.cpp b/stepmania/src/NoteDataUtil.cpp
index c4b727c87d..2574721908 100644
--- a/stepmania/src/NoteDataUtil.cpp
+++ b/stepmania/src/NoteDataUtil.cpp
@@ -1323,20 +1323,14 @@ void NoteDataUtil::CopyRightToLeft( NoteData &inout )
 
 void NoteDataUtil::ClearLeft( NoteData &inout )
 {
-	inout.ConvertHoldNotesTo4s();
 	for( int t=0; t<inout.GetNumTracks()/2; t++ )
-		FOREACH_NONEMPTY_ROW_IN_TRACK( inout, t, r )
-			inout.SetTapNote(t, r, TAP_EMPTY);
-	inout.Convert4sToHoldNotes();
+		inout.ClearRangeForTrack( 0, MAX_NOTE_ROW, t );
 }
 
 void NoteDataUtil::ClearRight( NoteData &inout )
 {
-	inout.ConvertHoldNotesTo4s();
 	for( int t=(inout.GetNumTracks()+1)/2; t<inout.GetNumTracks(); t++ )
-		FOREACH_NONEMPTY_ROW_IN_TRACK( inout, t, r )
-			inout.SetTapNote(t, r, TAP_EMPTY);
-	inout.Convert4sToHoldNotes();
+		inout.ClearRangeForTrack( 0, MAX_NOTE_ROW, t );
 }
 
 void NoteDataUtil::CollapseToOne( NoteData &inout )
@@ -1586,10 +1580,11 @@ void NoteDataUtil::Scale( NoteData &nd, float fScale )
 }
 #endif
 
-// added to fix things in the editor - make sure that you're working off data that is 
-// either in 4s or in 2s and 3s.
 void NoteDataUtil::ScaleRegion( NoteData &nd, float fScale, int iStartIndex, int iEndIndex )
 {
+	// convert to 2sAnd3s before calling this
+	ASSERT( nd.GetNumHoldNotes() == 0 );
+
 	ASSERT( fScale > 0 );
 	ASSERT( iStartIndex < iEndIndex );
 	ASSERT( iStartIndex >= 0 );