diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/ChunkManager.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/ChunkManager.java
index de5e308146..65b37318b7 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/ChunkManager.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/ChunkManager.java
@@ -14,6 +14,10 @@
 
 package com.google.gerrit.client.diff;
 
+import static com.google.gerrit.client.diff.OverviewBar.MarkType.DELETE;
+import static com.google.gerrit.client.diff.OverviewBar.MarkType.EDIT;
+import static com.google.gerrit.client.diff.OverviewBar.MarkType.INSERT;
+
 import com.google.gerrit.client.diff.DiffInfo.Region;
 import com.google.gerrit.client.diff.DiffInfo.Span;
 import com.google.gerrit.client.rpc.Natives;
@@ -143,11 +147,11 @@ class ChunkManager {
 
   private void addGutterTag(Region region, int startA, int startB) {
     if (region.a() == null) {
-      sidePanel.addGutter(cmB, startB, OverviewBar.GutterType.INSERT);
+      sidePanel.add(cmB, startB, region.b().length(), INSERT);
     } else if (region.b() == null) {
-      sidePanel.addGutter(cmA, startA, OverviewBar.GutterType.DELETE);
+      sidePanel.add(cmA, startA, region.a().length(), DELETE);
     } else {
-      sidePanel.addGutter(cmB, startB, OverviewBar.GutterType.EDIT);
+      sidePanel.add(cmB, startB, region.b().length(), EDIT);
     }
   }
 
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentBox.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentBox.java
index 0a6ee1af96..1d7452085c 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentBox.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentBox.java
@@ -15,7 +15,6 @@
 package com.google.gerrit.client.diff;
 
 import com.google.gerrit.client.changes.CommentInfo;
-import com.google.gerrit.client.diff.OverviewBar.GutterWrapper;
 import com.google.gwt.event.dom.client.MouseOutEvent;
 import com.google.gwt.event.dom.client.MouseOutHandler;
 import com.google.gwt.event.dom.client.MouseOverEvent;
@@ -34,7 +33,7 @@ abstract class CommentBox extends Composite {
   }
 
   private final CommentGroup group;
-  private GutterWrapper gutterWrapper;
+  private OverviewBar.MarkHandle mark;
   private FromTo fromTo;
   private TextMarker rangeMarker;
   private TextMarker rangeHighlightMarker;
@@ -80,8 +79,12 @@ abstract class CommentBox extends Composite {
     return group.getCommentManager();
   }
 
-  void setGutterWrapper(GutterWrapper wrapper) {
-    gutterWrapper = wrapper;
+  OverviewBar.MarkHandle getMark() {
+    return mark;
+  }
+
+  void setMark(OverviewBar.MarkHandle mh) {
+    mark = mh;
   }
 
   void setRangeHighlight(boolean highlight) {
@@ -106,10 +109,6 @@ abstract class CommentBox extends Composite {
     }
   }
 
-  GutterWrapper getGutterWrapper() {
-    return gutterWrapper;
-  }
-
   CodeMirror getCm() {
     return group.getCm();
   }
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentManager.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentManager.java
index 6531e385ef..517b5ff34f 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentManager.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/CommentManager.java
@@ -157,10 +157,10 @@ class CommentManager {
             getPatchSetIdFromSide(side),
             info);
         group.add(box);
-        box.setGutterWrapper(host.diffTable.overview.addGutter(
+        box.setMark(host.diffTable.overview.add(
             host.getCmFromSide(side),
-            Math.max(0, info.line() - 1),
-            OverviewBar.GutterType.COMMENT));
+            Math.max(0, info.line() - 1), 1,
+            OverviewBar.MarkType.COMMENT));
         published.put(info.id(), box);
       }
     }
@@ -220,10 +220,10 @@ class CommentManager {
     }
 
     group.add(box);
-    box.setGutterWrapper(host.diffTable.overview.addGutter(
+    box.setMark(host.diffTable.overview.add(
         host.getCmFromSide(side),
-        Math.max(0, info.line() - 1),
-        OverviewBar.GutterType.DRAFT));
+        Math.max(0, info.line() - 1), 1,
+        OverviewBar.MarkType.DRAFT));
     return box;
   }
 
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.ui.xml b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.ui.xml
index 9a90569856..2c201a7a57 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.ui.xml
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.ui.xml
@@ -58,11 +58,15 @@ limitations under the License.
     }
     .table td { padding: 0 }
     .a, .b { width: 50% }
-    .overview { width: 10px }
 
-    /* Hide left side scrollbar, right side controls both views. */
-    .a .CodeMirror-scroll { padding-right: 0; }
-    .a .CodeMirror-vscrollbar { display: none !important; }
+    .overview {
+      width: 10px;
+      vertical-align: top;
+    }
+
+    /* Hide scrollbars, OverviewBar controls both views. */
+    .difftable .CodeMirror-scroll { padding-right: 0; }
+    .difftable .CodeMirror-vscrollbar { display: none !important; }
 
     .showLineNumbers .b { border-left: none; }
     .b { border-left: 1px solid #ddd; }
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DraftBox.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DraftBox.java
index e4202fcb8f..edc79a5e92 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DraftBox.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DraftBox.java
@@ -233,7 +233,7 @@ class DraftBox extends CommentBox {
     getCommentManager().setUnsaved(this, false);
     setRangeHighlight(false);
     clearRange();
-    getGutterWrapper().remove();
+    getMark().remove();
     getCommentGroup().remove(this);
     getCm().focus();
   }
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/OverviewBar.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/OverviewBar.java
index b21a65a49d..a5df39ef9c 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/OverviewBar.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/OverviewBar.java
@@ -15,28 +15,34 @@
 package com.google.gerrit.client.diff;
 
 import com.google.gwt.core.client.GWT;
-import com.google.gwt.core.client.Scheduler;
-import com.google.gwt.core.client.Scheduler.ScheduledCommand;
+import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.Style.Unit;
 import com.google.gwt.event.dom.client.ClickEvent;
 import com.google.gwt.event.dom.client.ClickHandler;
-import com.google.gwt.event.shared.HandlerRegistration;
+import com.google.gwt.event.dom.client.MouseDownEvent;
+import com.google.gwt.event.dom.client.MouseMoveEvent;
+import com.google.gwt.event.dom.client.MouseUpEvent;
 import com.google.gwt.resources.client.CssResource;
 import com.google.gwt.uibinder.client.UiBinder;
 import com.google.gwt.uibinder.client.UiField;
+import com.google.gwt.uibinder.client.UiHandler;
+import com.google.gwt.user.client.DOM;
 import com.google.gwt.user.client.ui.Composite;
 import com.google.gwt.user.client.ui.HTMLPanel;
 import com.google.gwt.user.client.ui.Label;
+import com.google.gwt.user.client.ui.Widget;
 
 import net.codemirror.lib.CodeMirror;
 import net.codemirror.lib.LineCharacter;
+import net.codemirror.lib.ScrollInfo;
 
 import java.util.ArrayList;
-import java.util.Iterator;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 /** Displays overview of all edits and comments in this file. */
-class OverviewBar extends Composite {
+class OverviewBar extends Composite implements ClickHandler {
   interface Binder extends UiBinder<HTMLPanel, OverviewBar> {}
   private static final Binder uiBinder = GWT.create(Binder.class);
 
@@ -47,136 +53,199 @@ class OverviewBar extends Composite {
     String draft();
     String insert();
     String delete();
+    String viewportDrag();
   }
 
-  enum GutterType {
+  enum MarkType {
     COMMENT, DRAFT, INSERT, DELETE, EDIT
   }
 
-  @UiField
-  Style style;
+  @UiField Style style;
+  @UiField Label viewport;
 
-  private List<GutterWrapper> gutters;
+  private final List<MarkHandle> diff;
+  private final Set<MarkHandle> comments;
   private CodeMirror cmB;
 
+  private boolean dragging;
+  private int startY;
+  private double ratio;
+
   OverviewBar() {
     initWidget(uiBinder.createAndBindUi(this));
-    gutters = new ArrayList<GutterWrapper>();
+    diff = new ArrayList<MarkHandle>();
+    comments = new HashSet<MarkHandle>();
+    addDomHandler(this, ClickEvent.getType());
   }
 
-  GutterWrapper addGutter(CodeMirror cm, int line, GutterType type) {
-    Label gutter = new Label();
-    GutterWrapper info = new GutterWrapper(this, gutter, cm, line, type);
-    adjustGutter(info);
-    gutter.addStyleName(style.gutter());
+  void init(CodeMirror cmB) {
+    this.cmB = cmB;
+  }
+
+  void refresh() {
+    update(cmB.getScrollInfo());
+  }
+
+  void update(ScrollInfo si) {
+    double viewHeight = si.getClientHeight();
+    double r = ratio(si);
+
+    com.google.gwt.dom.client.Style style = viewport.getElement().getStyle();
+    style.setTop(si.getTop() * r, Unit.PX);
+    style.setHeight(Math.max(10, viewHeight * r), Unit.PX);
+    getElement().getStyle().setHeight(viewHeight, Unit.PX);
+
+    for (MarkHandle info : diff) {
+      info.position(r);
+    }
+    for (MarkHandle info : comments) {
+      info.position(r);
+    }
+  }
+
+  @Override
+  protected void onUnload() {
+    super.onUnload();
+    if (dragging) {
+      DOM.releaseCapture(viewport.getElement());
+    }
+  }
+
+  @Override
+  public void onClick(ClickEvent e) {
+    if (e.getY() < viewport.getElement().getOffsetTop()) {
+      CodeMirror.handleVimKey(cmB, "<PageUp>");
+    } else {
+      CodeMirror.handleVimKey(cmB, "<PageDown>");
+    }
+    cmB.focus();
+  }
+
+  @UiHandler("viewport")
+  void onMouseDown(MouseDownEvent e) {
+    if (cmB != null) {
+      dragging = true;
+      ratio = ratio(cmB.getScrollInfo());
+      startY = e.getY();
+      viewport.addStyleName(style.viewportDrag());
+      DOM.setCapture(viewport.getElement());
+      e.preventDefault();
+      e.stopPropagation();
+    }
+  }
+
+  @UiHandler("viewport")
+  void onMouseMove(MouseMoveEvent e) {
+    if (dragging) {
+      int y = e.getRelativeY(getElement()) - startY;
+      cmB.scrollToY(Math.max(0, y / ratio));
+      e.preventDefault();
+      e.stopPropagation();
+    }
+  }
+
+  @UiHandler("viewport")
+  void onMouseUp(MouseUpEvent e) {
+    if (dragging) {
+      dragging = false;
+      DOM.releaseCapture(viewport.getElement());
+      viewport.removeStyleName(style.viewportDrag());
+      e.preventDefault();
+      e.stopPropagation();
+    }
+  }
+
+  private double ratio(ScrollInfo si) {
+    double barHeight = si.getClientHeight();
+    double contentHeight = si.getHeight();
+    return barHeight / contentHeight;
+  }
+
+  MarkHandle add(CodeMirror cm, int line, int height, MarkType type) {
+    MarkHandle mark = new MarkHandle(cm, line, height);
     switch (type) {
       case COMMENT:
-        gutter.addStyleName(style.comment());
+        mark.addStyleName(style.comment());
+        comments.add(mark);
         break;
       case DRAFT:
-        gutter.addStyleName(style.draft());
-        gutter.setText("*");
+        mark.addStyleName(style.draft());
+        mark.getElement().setInnerText("*");
+        comments.add(mark);
         break;
       case INSERT:
-        gutter.addStyleName(style.insert());
+        mark.addStyleName(style.insert());
+        diff.add(mark);
         break;
       case DELETE:
-        gutter.addStyleName(style.delete());
+        mark.addStyleName(style.delete());
+        diff.add(mark);
         break;
       case EDIT:
-        gutter.addStyleName(style.insert());
-        Label labelLeft = new Label();
-        labelLeft.addStyleName(style.halfGutter());
-        gutter.getElement().appendChild(labelLeft.getElement());
+        mark.edit = DOM.createDiv();
+        mark.edit.setClassName(style.halfGutter());
+        mark.getElement().appendChild(mark.edit);
+        mark.addStyleName(style.insert());
+        diff.add(mark);
+        break;
     }
-    ((HTMLPanel) getWidget()).add(gutter);
-    gutters.add(info);
-    return info;
-  }
-
-  void adjustGutters(CodeMirror cmB) {
-    this.cmB = cmB;
-    Scheduler.get().scheduleDeferred(new ScheduledCommand() {
-      @Override
-      public void execute() {
-        for (GutterWrapper info : gutters) {
-          adjustGutter(info);
-        }
-      }
-    });
-  }
-
-  private void adjustGutter(GutterWrapper wrapper) {
-    if (cmB == null) {
-      return;
+    if (cmB != null) {
+      mark.position(ratio(cmB.getScrollInfo()));
     }
-    final CodeMirror cm = wrapper.cm;
-    final int line = wrapper.line;
-    Label gutter = wrapper.gutter;
-    final double height = cm.heightAtLine(line, "local");
-    final double scrollbarHeight = cmB.getScrollbarV().getClientHeight();
-    double top = height / cmB.getSizer().getClientHeight() *
-        scrollbarHeight +
-        cmB.getScrollbarV().getAbsoluteTop();
-    if (top == 0) {
-      top = -10;
+    ((HTMLPanel) getWidget()).add(mark);
+    return mark;
+  }
+
+  void clearDiffMarkers() {
+    for (MarkHandle mark : diff) {
+      mark.removeFromParent();
     }
-    gutter.getElement().getStyle().setTop(top, Unit.PX);
-    wrapper.replaceClickHandler(new ClickHandler() {
-      @Override
-      public void onClick(ClickEvent event) {
-        cm.setCursor(LineCharacter.create(line));
-        cm.scrollToY(height - 0.5 * scrollbarHeight);
-        cm.focus();
-      }
-    });
+    diff.clear();
   }
 
-  void removeGutter(GutterWrapper wrapper) {
-    gutters.remove(wrapper);
-  }
+  class MarkHandle extends Widget implements ClickHandler {
+    private static final int MIN_HEIGHT = 3;
 
-  @SuppressWarnings("incomplete-switch")
-  void clearDiffGutters() {
-    for (Iterator<GutterWrapper> i = gutters.iterator(); i.hasNext();) {
-      GutterWrapper wrapper = i.next();
-      switch (wrapper.type) {
-        case INSERT:
-        case DELETE:
-        case EDIT:
-          wrapper.gutter.removeFromParent();
-          i.remove();
-      }
-    }
-  }
+    private final CodeMirror cm;
+    private final int line;
+    private final int height;
+    private Element edit;
 
-  static class GutterWrapper {
-    private OverviewBar host;
-    private Label gutter;
-    private CodeMirror cm;
-    private int line;
-    private HandlerRegistration regClick;
-    private GutterType type;
-
-    GutterWrapper(OverviewBar host, Label anchor, CodeMirror cm, int line,
-        GutterType type) {
-      this.host = host;
-      this.gutter = anchor;
+    MarkHandle(CodeMirror cm, int line, int height) {
       this.cm = cm;
       this.line = line;
-      this.type = type;
+      this.height = height;
+
+      setElement(DOM.createDiv());
+      setStyleName(style.gutter());
+      addDomHandler(this, ClickEvent.getType());
     }
 
-    private void replaceClickHandler(ClickHandler newHandler) {
-      if (regClick != null) {
-        regClick.removeHandler();
+    void position(double ratio) {
+      double y = cm.heightAtLine(line, "local");
+      getElement().getStyle().setTop(y * ratio, Unit.PX);
+      if (height > 1) {
+        double e = cm.heightAtLine(line + height, "local");
+        double h = Math.max(MIN_HEIGHT, (e - y) * ratio);
+        getElement().getStyle().setHeight(h, Unit.PX);
+        if (edit != null) {
+          edit.getStyle().setHeight(h, Unit.PX);
+        }
       }
-      regClick = gutter.addClickHandler(newHandler);
+    }
+
+    @Override
+    public void onClick(ClickEvent event) {
+      double y = cm.heightAtLine(line, "local");
+      double viewport = cm.getScrollInfo().getClientHeight();
+      cm.setCursor(LineCharacter.create(line));
+      cm.scrollToY(y - 0.5 * viewport);
+      cm.focus();
     }
 
     void remove() {
-      gutter.removeFromParent();
-      host.removeGutter(this);
+      removeFromParent();
+      comments.remove(this);
     }
   }
 }
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/OverviewBar.ui.xml b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/OverviewBar.ui.xml
index bc693f55b4..a56c3da859 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/OverviewBar.ui.xml
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/OverviewBar.ui.xml
@@ -17,22 +17,27 @@ limitations under the License.
 <ui:UiBinder xmlns:ui='urn:ui:com.google.gwt.uibinder'
     xmlns:g='urn:import:com.google.gwt.user.client.ui'>
   <ui:style type='com.google.gerrit.client.diff.OverviewBar.Style'>
+    .overview {
+      position: relative;
+    }
     .gutter {
       cursor: pointer;
-      position: fixed;
+      position: absolute;
       height: 3px;
-      width: 10px;
-      border: 1px solid black;
+      width: 6px;
+      border: 1px solid grey;
+      margin-left: 1px;
     }
     .halfGutter {
       cursor: pointer;
-      position: fixed;
+      position: absolute;
       height: 3px;
-      width: 5px;
+      width: 3px;
       background-color: #faa;
     }
     .comment, .draft {
-      background-color: #e5ecf9;
+      background-color: #fcfa96;
+      z-index: 2;
     }
     .draft {
       text-align: center;
@@ -47,6 +52,20 @@ limitations under the License.
     .insert {
       background-color: #9f9;
     }
+    .viewport {
+      position: absolute;
+      background-color: rgba(128, 128, 128, 0.50);
+      border: 1px solid #444;
+      width: 8px;
+      cursor: default;
+      z-index: 3;
+      border-radius: 4px;
+    }
+    .viewportDrag {
+      cursor: move;
+    }
   </ui:style>
-  <g:HTMLPanel/>
-</ui:UiBinder>
\ No newline at end of file
+  <g:HTMLPanel styleName='{style.overview}'>
+    <g:Label ui:field='viewport' styleName='{style.viewport}'/>
+  </g:HTMLPanel>
+</ui:UiBinder>
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/ScrollSynchronizer.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/ScrollSynchronizer.java
index 85f2c9348f..ba742025a9 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/ScrollSynchronizer.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/ScrollSynchronizer.java
@@ -22,6 +22,7 @@ import net.codemirror.lib.ScrollInfo;
 class ScrollSynchronizer {
   private DiffTable diffTable;
   private LineMapper mapper;
+  private OverviewBar overview;
   private ScrollCallback active;
 
   ScrollSynchronizer(DiffTable diffTable,
@@ -29,6 +30,7 @@ class ScrollSynchronizer {
       LineMapper mapper) {
     this.diffTable = diffTable;
     this.mapper = mapper;
+    this.overview = diffTable.overview;
 
     cmA.on("scroll", new ScrollCallback(cmA, cmB, DisplaySide.A));
     cmB.on("scroll", new ScrollCallback(cmB, cmA, DisplaySide.B));
@@ -73,6 +75,7 @@ class ScrollSynchronizer {
       if (active == this) {
         ScrollInfo si = src.getScrollInfo();
         updateScreenHeader(si);
+        overview.update(si);
         dst.scrollTo(si.getLeft(), align(si.getTop()));
         state = 0;
       }
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.java
index ebc767b56b..59523551e8 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.java
@@ -64,7 +64,6 @@ import net.codemirror.lib.CodeMirror.BeforeSelectionChangeHandler;
 import net.codemirror.lib.CodeMirror.GutterClickHandler;
 import net.codemirror.lib.CodeMirror.LineClassWhere;
 import net.codemirror.lib.CodeMirror.LineHandle;
-import net.codemirror.lib.CodeMirror.Viewport;
 import net.codemirror.lib.Configuration;
 import net.codemirror.lib.KeyMap;
 import net.codemirror.lib.LineCharacter;
@@ -228,7 +227,7 @@ public class SideBySide2 extends Screen {
       }
     });
     setLineLength(prefs.lineLength());
-    diffTable.overview.adjustGutters(cmB);
+    diffTable.overview.refresh();
 
     if (startLine == 0 && diff.meta_b() != null) {
       DiffChunkInfo d = chunkManager.getFirst();
@@ -294,7 +293,6 @@ public class SideBySide2 extends Screen {
     cm.on("beforeSelectionChange", onSelectionChange(cm));
     cm.on("cursorActivity", updateActiveLine(cm));
     cm.on("gutterClick", onGutterClick(cm));
-    cm.on("viewportChange", adjustGutters(cm));
     cm.on("focus", updateActiveLine(cm));
     cm.addKeyMap(KeyMap.create()
         .on("'a'", upToChange(true))
@@ -466,6 +464,7 @@ public class SideBySide2 extends Screen {
 
     cmA = newCM(diff.meta_a(), diff.text_a(), DisplaySide.A, diffTable.cmA);
     cmB = newCM(diff.meta_b(), diff.text_b(), DisplaySide.B, diffTable.cmB);
+    diffTable.overview.init(cmB);
     chunkManager = new ChunkManager(this, cmA, cmB, diffTable.overview);
     skipManager = new SkipManager(this, commentManager);
 
@@ -606,6 +605,7 @@ public class SideBySide2 extends Screen {
       public void run() {
         skipManager.removeAll();
         skipManager.render(context, diff);
+        diffTable.overview.refresh();
       }
     });
   }
@@ -636,21 +636,6 @@ public class SideBySide2 extends Screen {
     }
   }
 
-  private Runnable adjustGutters(final CodeMirror cm) {
-    return new Runnable() {
-      @Override
-      public void run() {
-        Viewport fromTo = cm.getViewport();
-        int size = fromTo.getTo() - fromTo.getFrom() + 1;
-        if (cm.getOldViewportSize() == size) {
-          return;
-        }
-        cm.setOldViewportSize(size);
-        diffTable.overview.adjustGutters(cmB);
-      }
-    };
-  }
-
   private Runnable updateActiveLine(final CodeMirror cm) {
     final CodeMirror other = otherCm(cm);
     return new Runnable() {
@@ -789,7 +774,7 @@ public class SideBySide2 extends Screen {
     int height = getCodeMirrorHeight();
     cmA.setHeight(height);
     cmB.setHeight(height);
-    diffTable.overview.adjustGutters(cmB);
+    diffTable.overview.refresh();
   }
 
   private int getCodeMirrorHeight() {
@@ -886,7 +871,7 @@ public class SideBySide2 extends Screen {
               public void run() {
                 skipManager.removeAll();
                 chunkManager.reset();
-                diffTable.overview.clearDiffGutters();
+                diffTable.overview.clearDiffMarkers();
                 setShowIntraline(prefs.intralineDifference());
                 render(diff);
                 skipManager.render(prefs.context(), diff);
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.ui.xml b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.ui.xml
index 1bc707a3a5..8c26873403 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.ui.xml
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.ui.xml
@@ -17,7 +17,13 @@ limitations under the License.
 <ui:UiBinder xmlns:ui='urn:ui:com.google.gwt.uibinder'
     xmlns:g='urn:import:com.google.gwt.user.client.ui'
     xmlns:d='urn:import:com.google.gerrit.client.diff'>
-  <g:FlowPanel>
+  <ui:style>
+    .sbs2 {
+      margin-left: -5px;
+      margin-right: -5px;
+    }
+  </ui:style>
+  <g:FlowPanel styleName='{style.sbs2}'>
     <d:Header ui:field='header'/>
     <d:DiffTable ui:field='diffTable'/>
   </g:FlowPanel>
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SkipBar.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SkipBar.java
index 265bb3e78b..351f02680b 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SkipBar.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SkipBar.java
@@ -132,6 +132,7 @@ class SkipBar extends Composite {
   void expandBefore(int cnt) {
     expandSideBefore(cnt);
     otherBar.expandSideBefore(cnt);
+    manager.getOverviewBar().refresh();
   }
 
   private void expandSideBefore(int cnt) {
@@ -183,6 +184,7 @@ class SkipBar extends Composite {
     expandSideAll();
     otherBar.expandSideAll();
     manager.remove(this, otherBar);
+    manager.getOverviewBar().refresh();
   }
 
   @UiHandler("upArrow")
@@ -195,6 +197,7 @@ class SkipBar extends Composite {
   void onExpandAfter(ClickEvent e) {
     expandAfter();
     otherBar.expandAfter();
+    manager.getOverviewBar().refresh();
     cm.focus();
   }
 }
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SkipManager.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SkipManager.java
index 1e8c1ca20a..d55f625f01 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SkipManager.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SkipManager.java
@@ -38,6 +38,10 @@ class SkipManager {
     this.commentManager = commentManager;
   }
 
+  OverviewBar getOverviewBar() {
+    return host.diffTable.overview;
+  }
+
   void render(int context, DiffInfo diff) {
     if (context == AccountDiffPreference.WHOLE_FILE_CONTEXT) {
       return;
@@ -106,6 +110,7 @@ class SkipManager {
       for (SkipBar bar : skipBars) {
         bar.expandSideAll();
       }
+      getOverviewBar().refresh();
       skipBars = null;
       line0 = null;
     }
diff --git a/gerrit-gwtui/src/main/java/net/codemirror/lib/CodeMirror.java b/gerrit-gwtui/src/main/java/net/codemirror/lib/CodeMirror.java
index 16150752c1..c0247c6618 100644
--- a/gerrit-gwtui/src/main/java/net/codemirror/lib/CodeMirror.java
+++ b/gerrit-gwtui/src/main/java/net/codemirror/lib/CodeMirror.java
@@ -168,14 +168,6 @@ public class CodeMirror extends JavaScriptObject {
     return this.getViewport();
   }-*/;
 
-  public final native int getOldViewportSize() /*-{
-    return this.state.oldViewportSize || 0;
-  }-*/;
-
-  public final native void setOldViewportSize(int lines) /*-{
-    this.state.oldViewportSize = lines;
-  }-*/;
-
   public final native void operation(Runnable thunk) /*-{
     this.operation(function() {
       thunk.@java.lang.Runnable::run()();
diff --git a/gerrit-gwtui/src/main/java/net/codemirror/lib/ScrollInfo.java b/gerrit-gwtui/src/main/java/net/codemirror/lib/ScrollInfo.java
index 06394166cb..096f1adcf8 100644
--- a/gerrit-gwtui/src/main/java/net/codemirror/lib/ScrollInfo.java
+++ b/gerrit-gwtui/src/main/java/net/codemirror/lib/ScrollInfo.java
@@ -16,19 +16,22 @@ package net.codemirror.lib;
 
 import com.google.gwt.core.client.JavaScriptObject;
 
-/** {left, top, width, height, clientWidth, clientHeight} objects returned by
- * getScrollInfo(). */
+/** Returned by {@link CodeMirror#getScrollInfo()}. */
 public class ScrollInfo extends JavaScriptObject {
-  public static ScrollInfo create() {
-    return createObject().cast();
-  }
-
   public final native double getLeft() /*-{ return this.left; }-*/;
   public final native double getTop() /*-{ return this.top; }-*/;
-  public final native double getWidth() /*-{ return this.width; }-*/;
+
+  /**
+   * Pixel height of the full content being scrolled. This may only be an
+   * estimate given by CodeMirror. Line widgets further down in the document may
+   * not be measured, so line heights can be incorrect until drawn.
+   */
   public final native double getHeight() /*-{ return this.height; }-*/;
-  public final native double getClientWidth() /*-{ return this.clientWidth; }-*/;
+  public final native double getWidth() /*-{ return this.width; }-*/;
+
+  /** Visible height of the viewport, excluding scrollbars. */
   public final native double getClientHeight() /*-{ return this.clientHeight; }-*/;
+  public final native double getClientWidth() /*-{ return this.clientWidth; }-*/;
 
   protected ScrollInfo() {
   }