diff --git a/com.minres.scviewer.database.ui.swt/src/com/minres/scviewer/database/swt/internal/WaveformCanvas.java b/com.minres.scviewer.database.ui.swt/src/com/minres/scviewer/database/swt/internal/WaveformCanvas.java
index 0da478c..35ccff3 100644
--- a/com.minres.scviewer.database.ui.swt/src/com/minres/scviewer/database/swt/internal/WaveformCanvas.java
+++ b/com.minres.scviewer.database.ui.swt/src/com/minres/scviewer/database/swt/internal/WaveformCanvas.java
@@ -229,6 +229,11 @@ public class WaveformCanvas extends Canvas{
     }
 
     public void setZoomLevel(int level) {
+		long tc=cursorPainters.get(0).getTime(); // cursor time
+		setZoomLevel(level, tc);
+    }
+
+    public void setZoomLevel(int level, long centerTime) {
     	long oldScaleFactor=scaleFactor;
     	if(level<Constants.unitMultiplier.length*Constants.unitString.length){
     		this.level = level;
@@ -242,10 +247,9 @@ public class WaveformCanvas extends Canvas{
     		 * xcn = tc/newScaleFactor
     		 * t0n = (xcn-xoffs)*scaleFactor
     		 */
-    		long tc=cursorPainters.get(0).getTime(); // cursor time
-    		long xc=tc/oldScaleFactor; // cursor total x-offset
+    		long xc=centerTime/oldScaleFactor; // cursor total x-offset
     		long xoffs=xc+origin.x; // cursor offset relative to left border
-    		long xcn=tc/scaleFactor; // new total x-offset
+    		long xcn=centerTime/scaleFactor; // new total x-offset
     		long originX=xcn-xoffs;
     		if(originX>0) {
     			origin.x=(int) -originX; // new cursor time offset relative to left border
@@ -557,7 +561,7 @@ public class WaveformCanvas extends Canvas{
     	return (getClientArea().width+origin.x)*scaleFactor;
     }
 
-    long getOriginTime() {
+    long getMinVisibleTime() {
     	return origin.x * scaleFactor;
     }
 }
diff --git a/com.minres.scviewer.database.ui.swt/src/com/minres/scviewer/database/swt/internal/WaveformViewer.java b/com.minres.scviewer.database.ui.swt/src/com/minres/scviewer/database/swt/internal/WaveformViewer.java
index f94976a..9b959d4 100644
--- a/com.minres.scviewer.database.ui.swt/src/com/minres/scviewer/database/swt/internal/WaveformViewer.java
+++ b/com.minres.scviewer.database.ui.swt/src/com/minres/scviewer/database/swt/internal/WaveformViewer.java
@@ -194,26 +194,60 @@ public class WaveformViewer implements IWaveformViewer  {
 			if((e.stateMask&SWT.MODIFIER_MASK&~SWT.SHIFT)!=0) return; //don't react on modifier except shift
 			if(!start.equals(end)){
 				asyncUpdate(e.widget);
+				long startTime = waveformCanvas.getTimeForOffset(start.x);
+				long endTime = waveformCanvas.getTimeForOffset(end.x);
+				long targetTimeRange = endTime-startTime;
+				long currentTimeRange = waveformCanvas.getMaxVisibleTime()-waveformCanvas.getMinVisibleTime();
+				if(targetTimeRange==0) return;
+				long relation = currentTimeRange/targetTimeRange;
+				long i = 1;
+				int level=0;//relation>0?0:0;
+				do {
+					if(relation<0 ) {
+						if(-relation<i) {
+							break;
+						}
+						level--;
+						if(-relation<i*3) {
+							break;
+						}
+						level--;						
+					} else {
+						if(relation<i) {
+							break;
+						}
+						level++;
+						if(relation<i*3) {
+							break;
+						}
+						level++;
+					}
+					i=i*10;
+				} while(i<10000);
+				if(i<10000) {
+					int curLevel = waveformCanvas.getZoomLevel();
+					waveformCanvas.setZoomLevel(curLevel-level, (startTime+endTime)/2);
+				}
 			} else if (e.button ==  1 && ((e.stateMask&SWT.SHIFT)==0)) {
 				// set cursor (button 1 and no shift)
 				if(Math.abs(e.x-start.x)<3 && Math.abs(e.y-start.y)<3){				
 					// first set cursor time
-					setCursorTime(snapOffsetToEvent(e));
+					setCursorTime(snapOffsetToEvent(start));
 					// then set selection and reveal
 					setSelection(new StructuredSelection(initialSelected));
 					asyncUpdate(e.widget);
 				}
 			}else if (e.button ==  2 ||(e.button==1 && (e.stateMask&SWT.SHIFT)!=0)) {
 				// set marker (button 1 and shift)
-				setMarkerTime(snapOffsetToEvent(e), selectedMarker);
+				setMarkerTime(snapOffsetToEvent(start), selectedMarker);
 				asyncUpdate(e.widget);
 			}        
 		}
 		
-		protected long snapOffsetToEvent(MouseEvent e) {
-			long time= waveformCanvas.getTimeForOffset(e.x);
+		protected long snapOffsetToEvent(Point p) {
+			long time= waveformCanvas.getTimeForOffset(p.x);
 			long scaling=5*waveformCanvas.getScaleFactor();
-			for(Object o:waveformCanvas.getClicked(start)){
+			for(Object o:waveformCanvas.getClicked(p)){
 				Entry<Long, ?> floorEntry=null, ceilEntry=null;
 				if(o instanceof TrackEntry){ 
 					TrackEntry entry = (TrackEntry) o;
@@ -1270,13 +1304,6 @@ public class WaveformViewer implements IWaveformViewer  {
 		if(percent<-100) percent=-100;
 		if(percent>100) percent=100;
 		int diff = (waveformCanvas.getWidth()*percent)/100;
-//		ScrollBar sb = waveformCanvas.getHorizontalBar();
-//		int x = sb.getSelection();
-//		System.out.println("Setting sb to "+ (x+diff));
-//		if((x+diff)>0)
-//			sb.setSelection(x+diff);
-//		else
-//			sb.setSelection(0);
 		Point o = waveformCanvas.getOrigin();
 		waveformCanvas.setOrigin(o.x-diff, o.y);
 		waveformCanvas.redraw();