diff --git a/plugins/org.eclipse.dd.mi/src/org/eclipse/dd/mi/service/command/commands/MIDataListRegisterValues.java b/plugins/org.eclipse.dd.mi/src/org/eclipse/dd/mi/service/command/commands/MIDataListRegisterValues.java
index a3d6031bf92..ee212145fec 100644
--- a/plugins/org.eclipse.dd.mi/src/org/eclipse/dd/mi/service/command/commands/MIDataListRegisterValues.java
+++ b/plugins/org.eclipse.dd.mi/src/org/eclipse/dd/mi/service/command/commands/MIDataListRegisterValues.java
@@ -89,6 +89,11 @@ public class MIDataListRegisterValues extends MICommand<MIDataListRegisterValues
         if (! (command instanceof  MIDataListRegisterValues) ) return null;    
         
         MIDataListRegisterValues  cmd = (MIDataListRegisterValues) command;
+        
+        /*
+         * If the format is different then this cannot be added to the list.
+         */
+        if ( fFmt != cmd.fFmt ) return null;
 
         int[] newregnos = new int[ regnums.length + cmd.regnums.length];