X-Git-Url: http://git.phpeclipse.com

diff --git a/net.sourceforge.phpeclipse.debug.core/src/net/sourceforge/phpdt/internal/debug/core/model/PHPStackFrame.java b/net.sourceforge.phpeclipse.debug.core/src/net/sourceforge/phpdt/internal/debug/core/model/PHPStackFrame.java
index dfac692..245dc76 100644
--- a/net.sourceforge.phpeclipse.debug.core/src/net/sourceforge/phpdt/internal/debug/core/model/PHPStackFrame.java
+++ b/net.sourceforge.phpeclipse.debug.core/src/net/sourceforge/phpdt/internal/debug/core/model/PHPStackFrame.java
@@ -608,18 +608,20 @@ public class PHPStackFrame extends PHPDebugElement implements IStackFrame, Compa
 	 * @return
 	 * <ul>
 	 * <li> -1 if the index of this stackframe is less.
-	 * <li> 0 if the index of both stackfream is equal (should no happen).
-	 * <li> 1 if the index of this stackfram is greater.
+	 * <li> 0 if the index of both stackframes are equal (should no happen).
+	 * <li> 1 if the index of this stackframe is greater.
 	 * </ul>
 	 */
 	public int compareTo(Object obj) {
-		//if (index < ((PHPStackFrame) obj).getIndex()) {
-		//	return -1;
-		//} else if (index > ((PHPStackFrame) obj).getIndex()) {
-		//	return 1;
-		//}
-
-		//return 0;
-		return Integer.signum(index - ((PHPStackFrame) obj).getIndex());
+		if (!(obj instanceof PHPStackFrame)) {
+			throw new IllegalArgumentException("A PHPStackFrame can only be compared with another PHPStackFrame");
+		}
+		int frameIndex = ((PHPStackFrame) obj).getIndex();
+		if (index < frameIndex) {
+			return -1;
+		} else if (index > frameIndex) {
+			return 1;
+		}
+		return 0;
 	}
 }