Fixed bug: 36348
diff --git a/org.eclipse.search/search/org/eclipse/search/internal/ui/Search.java b/org.eclipse.search/search/org/eclipse/search/internal/ui/Search.java
index 231f2da..9a78101 100644
--- a/org.eclipse.search/search/org/eclipse/search/internal/ui/Search.java
+++ b/org.eclipse.search/search/org/eclipse/search/internal/ui/Search.java
@@ -159,7 +159,7 @@
 	}
 	
 	boolean isSameSearch(Search search) {
-		return search != null && search.getOperation() == fOperation;
+		return search != null && search.getOperation() == fOperation && fOperation != null;
 	}
 	
 	void backupMarkers() {