#1977 P25 FQSUID handling improvements. P25 fully qualified radio/talkgroup identifiers we're being flagged as invalid when ISSI patch assigned a local address/ID of zero. Changes format of FQSUID and FQTGID to use a value of zero for the local alias when the call type is an ISSI patch and suppress display of the 0 alias value. If the identifier represents a roaming user, then the local address value is displayed with the FQSUID appended in parenthesis. (#1978)

Co-authored-by: Dennis Sheirer <dsheirer@github.com>

src/main/java/io/github/dsheirer/source/tuner/frequency/FrequencyController.java

@@ -300,15 +300,18 @@ public class FrequencyController
      */
     public void removeSourceEventProcessor(ISourceEventProcessor processor)
     {
-        mTunable.getLock().lock();
+        if(mTunable != null)
+        {
+            mTunable.getLock().lock();
 
-        try
-        {
-            mProcessors.remove(processor);
-        }
-        finally
-        {
-            mTunable.getLock().unlock();
+            try
+            {
+                mProcessors.remove(processor);
+            }
+            finally
+            {
+                mTunable.getLock().unlock();
+            }
         }
     }