--- old/application/org.openjdk.jmc.ui/src/main/java/org/openjdk/jmc/ui/misc/ChartCanvas.java	2019-05-09 10:24:57.356217006 -0400
+++ new/application/org.openjdk.jmc.ui/src/main/java/org/openjdk/jmc/ui/misc/ChartCanvas.java	2019-05-09 10:24:57.288216297 -0400
@@ -77,6 +77,7 @@
 	private int lastMouseX = -1;
 	private int lastMouseY = -1;
 	private List<Rectangle2D> highlightRects;
+	private Object hoveredItemData;
 
 	private class Selector extends MouseAdapter implements MouseMoveListener, MouseTrackListener {
 
@@ -152,6 +153,7 @@
 
 		@Override
 		public void mouseExit(MouseEvent e) {
+			resetHoveredItemData();
 			clearHighlightRects();
 		}
 
@@ -391,6 +393,18 @@
 		return (int) Math.round(x / xScale);
 	}
 
+	public Object getHoveredItemData() {
+		return this.hoveredItemData;
+	}
+
+	public void setHoveredItemData(Object data) {
+		this.hoveredItemData = data;
+	}
+
+	public void resetHoveredItemData() {
+		this.hoveredItemData = null;
+	}
+
 	private void updateHighlightRects() {
 		List<Rectangle2D> newRects = new ArrayList<>();
 		infoAt(new IChartInfoVisitor.Adapter() {
@@ -420,6 +434,13 @@
 			public void visit(ILane lane) {
 				// FIXME: Do we want this highlighted?
 			}
+
+			@Override
+			public void hover(Object data) {
+				if (data != null) {
+					setHoveredItemData(data);
+				}
+			}
 		}, lastMouseX, lastMouseY);
 		// Attempt to reduce flicker by avoiding unnecessary updates.
 		if (!newRects.equals(highlightRects)) {