diff --git a/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupEditor.java b/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupEditor.java
index 8f50a5cc..9d0a37c3 100644
--- a/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupEditor.java
+++ b/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupEditor.java
@@ -193,6 +193,11 @@ public class TalkgroupEditor extends DocumentListenerEditor<AliasID>
         {
             Protocol protocol = mComboProtocol.getItemAt(mComboProtocol.getSelectedIndex());
 
+            if(protocol == null)
+            {
+                protocol = Protocol.UNKNOWN;
+            }
+
             int value = -1;
 
             try
diff --git a/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupFormat.java b/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupFormat.java
index 213ffd6d..e904cf00 100644
--- a/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupFormat.java
+++ b/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupFormat.java
@@ -83,6 +83,14 @@ public enum TalkgroupFormat
         return mMaximumValue;
     }
 
+    /**
+     * Indicates if the value is valid for the protocol
+     */
+    public boolean isValid(int value)
+    {
+        return getMinimumValidValue() <= value && value <= getMaximumValidValue();
+    }
+
     /**
      * Short description of the valid value range
      */
@@ -99,9 +107,14 @@ public enum TalkgroupFormat
         return mValidRangeHelpText;
     }
 
-    public static TalkgroupFormat get(Protocol prococol)
+    public static TalkgroupFormat get(Protocol protocol)
     {
-        switch(prococol)
+        if(protocol == null)
+        {
+            return UNKNOWN;
+        }
+
+        switch(protocol)
         {
             case APCO25:
                 return APCO25;
diff --git a/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupRangeEditor.java b/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupRangeEditor.java
index 312e5676..dca54176 100644
--- a/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupRangeEditor.java
+++ b/src/main/java/io/github/dsheirer/alias/id/talkgroup/TalkgroupRangeEditor.java
@@ -174,6 +174,8 @@ public class TalkgroupRangeEditor extends DocumentListenerEditor<AliasID>
 
         TalkgroupRange talkgroupRange = getTalkgroupRange();
 
+        updateEditor(talkgroupRange.getProtocol());
+
         if(talkgroupRange != null)
         {
             mComboProtocol.getModel().setSelectedItem(talkgroupRange.getProtocol());
@@ -202,6 +204,12 @@ public class TalkgroupRangeEditor extends DocumentListenerEditor<AliasID>
         if(talkgroupRange != null)
         {
             Protocol protocol = mComboProtocol.getItemAt(mComboProtocol.getSelectedIndex());
+
+            if(protocol == null)
+            {
+                protocol = Protocol.UNKNOWN;
+            }
+
             talkgroupRange.setProtocol(protocol);
 
             int minValue = -1;