diff --git a/Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/popup/PopupRegulator.java b/Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/popup/PopupRegulator.java
index 50445c0f64..1a004061c8 100644
--- a/Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/popup/PopupRegulator.java
+++ b/Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/popup/PopupRegulator.java
@@ -15,6 +15,7 @@
  */
 package ghidra.graph.viewer.popup;
 
+import java.awt.Component;
 import java.awt.Window;
 import java.awt.event.*;
 
@@ -129,6 +130,13 @@ public class PopupRegulator<V, E> {
 			return;
 		}
 
+		Component c = event.getComponent();
+		if (!c.isShowing()) {
+			// This method is called from a a timer.  It is possible that the graph has been 
+			// closed by the time this method is called.
+			return;
+		}
+
 		ToolTipInfo<?> toolTipInfo = popupSource.getToolTipInfo(event);
 		JComponent toolTipComponent = toolTipInfo.getToolTipComponent();
 		boolean isCustomJavaTooltip = !(toolTipComponent instanceof JToolTip);