diff --git a/src/main/java/io/github/dsheirer/controller/channel/ChannelController.java b/src/main/java/io/github/dsheirer/controller/channel/ChannelController.java
index de1b7cde..06d1becb 100644
--- a/src/main/java/io/github/dsheirer/controller/channel/ChannelController.java
+++ b/src/main/java/io/github/dsheirer/controller/channel/ChannelController.java
@@ -1,3 +1,18 @@
+/*******************************************************************************
+ * sdr-trunk
+ * Copyright (C) 2014-2018 Dennis Sheirer
+ *
+ * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public
+ * License as published by  the Free Software Foundation, either version 3 of the License, or  (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful,  but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License  along with this program.
+ * If not, see <http://www.gnu.org/licenses/>
+ *
+ ******************************************************************************/
 package io.github.dsheirer.controller.channel;
 
 import com.jidesoft.swing.JideSplitPane;
@@ -24,8 +39,7 @@ import java.awt.Rectangle;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
 
-public class ChannelController extends JPanel 
-				implements ActionListener, ListSelectionListener
+public class ChannelController extends JPanel implements ActionListener, ListSelectionListener
 {
 	private static final long serialVersionUID = 1L;
 
@@ -168,9 +182,13 @@ public class ChannelController extends JPanel
 		if( index >= 0 )
 		{
 			int translatedIndex = mChannelTable.convertRowIndexToView( index );
-			mChannelTable.setRowSelectionInterval( translatedIndex, translatedIndex );
-			mChannelTable.scrollRectToVisible( 
-				new Rectangle( mChannelTable.getCellRect( translatedIndex, 0, true ) ) );
+
+			if(translatedIndex >= 0)
+			{
+				mChannelTable.setRowSelectionInterval( translatedIndex, translatedIndex );
+				mChannelTable.scrollRectToVisible(
+					new Rectangle( mChannelTable.getCellRect( translatedIndex, 0, true ) ) );
+			}
 		}
 	}
 	
diff --git a/src/main/java/io/github/dsheirer/source/tuner/TunerModel.java b/src/main/java/io/github/dsheirer/source/tuner/TunerModel.java
index 3350bcae..3b904a83 100644
--- a/src/main/java/io/github/dsheirer/source/tuner/TunerModel.java
+++ b/src/main/java/io/github/dsheirer/source/tuner/TunerModel.java
@@ -289,15 +289,7 @@ public class TunerModel extends AbstractTableModel implements Listener<TunerEven
                     }
                 case CHANNEL_COUNT:
                     int channelCount = tuner.getChannelSourceManager().getTunerChannelCount();
-
-                    if(channelCount > 0)
-                    {
-                        return channelCount + " (LOCKED)";
-                    }
-                    else
-                    {
-                        return "0";
-                    }
+                    return channelCount + " (" + (tuner.getTunerController().isLocked() ? "LOCKED)" : "UNLOCKED)");
                 case FREQUENCY_ERROR:
                     double ppm = tuner.getTunerController().getFrequencyCorrection();
                     return mFrequencyErrorPPMFormat.format(ppm);
diff --git a/src/main/java/io/github/dsheirer/source/tuner/manager/HeterodyneChannelSourceManager.java b/src/main/java/io/github/dsheirer/source/tuner/manager/HeterodyneChannelSourceManager.java
index 3e6e8545..8520146a 100644
--- a/src/main/java/io/github/dsheirer/source/tuner/manager/HeterodyneChannelSourceManager.java
+++ b/src/main/java/io/github/dsheirer/source/tuner/manager/HeterodyneChannelSourceManager.java
@@ -85,6 +85,10 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
                 //Add to the channel list and update the tuner center frequency as needed
                 mTunerChannels.add(tunerChannel);
                 updateTunerFrequency();
+
+                //Lock the tuner controller frequency and sample rate
+                mTunerController.setLocked(true);
+
                 broadcast(SourceEvent.channelCountChange(getTunerChannelCount()));
 
                 return tunerChannelSource;
@@ -138,6 +142,8 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
                 broadcastToChannels(tunerSourceEvent);
                 break;
             case NOTIFICATION_SAMPLE_RATE_CHANGE:
+            case NOTIFICATION_FREQUENCY_AND_SAMPLE_RATE_LOCKED:
+            case NOTIFICATION_FREQUENCY_AND_SAMPLE_RATE_UNLOCKED:
                 //no-op
                 break;
             default:
@@ -205,6 +211,12 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
                         mChannelSources.remove(channelSource);
                         mTunerChannels.remove(channelSource.getTunerChannel());
                         channelSource.dispose();
+
+                        //Unlock the tuner controller if there are no more channels
+                        if(getTunerChannelCount() == 0)
+                        {
+                            mTunerController.setLocked(false);
+                        }
                         broadcast(SourceEvent.channelCountChange(getTunerChannelCount()));
                     }
                     break;
@@ -212,8 +224,12 @@ public class HeterodyneChannelSourceManager extends ChannelSourceManager
                     //Rebroadcast so that the tuner source can process this event
                     broadcast(sourceEvent);
                     break;
+                case NOTIFICATION_CHANNEL_COUNT_CHANGE:
+                    //Lock the tuner controller frequency & sample rate when we're processing channels
+                    break;
                 default:
                     mLog.info("Unrecognized Source Event received from channel: " + sourceEvent);
+                    break;
             }
         }
     }