Disable Spark automatic scroll on activity

spark.patch

Index: src/java/org/jivesoftware/spark/ui/ChatArea.java
===================================================================
--- src/java/org/jivesoftware/spark/ui/ChatArea.java	(revision 13060)
+++ src/java/org/jivesoftware/spark/ui/ChatArea.java	(working copy)
@@ -298,7 +298,7 @@
         final Document doc = getDocument();
         styles.removeAttribute("link");
         doc.insertString(doc.getLength(), text, styles);
-        setCaretPosition(doc.getLength());
+        //setCaretPosition(doc.getLength());
     }
 
     /**
@@ -312,7 +312,7 @@
         final Document doc = getDocument();
         StyleConstants.setForeground(styles, color);
         doc.insertString(doc.getLength(), text, styles);
-        setCaretPosition(doc.getLength());
+        //setCaretPosition(doc.getLength());
     }
 
     /**
@@ -332,7 +332,7 @@
         StyleConstants.setForeground(styles, (Color)UIManager.get("TextPane.foreground"));
         styles.removeAttribute("link");
         setCharacterAttributes(styles, false);
-        setCaretPosition(doc.getLength());
+        //setCaretPosition(doc.getLength());
 
     }
     
@@ -353,7 +353,7 @@
         StyleConstants.setForeground(styles, (Color)UIManager.get("TextPane.foreground"));
         styles.removeAttribute("link");
         setCharacterAttributes(styles, false);
-        setCaretPosition(doc.getLength());
+        //setCaretPosition(doc.getLength());
 
     }
 
@@ -376,7 +376,7 @@
 
         select(doc.getLength(), doc.getLength());
         insertIcon(emotion);
-        setCaretPosition(doc.getLength());
+        //setCaretPosition(doc.getLength());
 
         return true;
     }
Index: src/java/org/jivesoftware/spark/ui/ChatRoom.java
===================================================================
--- src/java/org/jivesoftware/spark/ui/ChatRoom.java	(revision 13060)
+++ src/java/org/jivesoftware/spark/ui/ChatRoom.java	(working copy)
@@ -63,6 +63,7 @@
 import javax.swing.event.DocumentListener;
 import javax.swing.text.BadLocationException;
 import javax.swing.text.Document;
+import javax.swing.text.DefaultCaret;
 
 import org.jivesoftware.resource.Res;
 import org.jivesoftware.resource.SparkRes;
@@ -132,6 +133,8 @@
     protected ChatRoom() {
         chatPanel = new JPanel(new GridBagLayout());
         transcriptWindow = UIComponentRegistry.createTranscriptWindow();
+        DefaultCaret caret = (DefaultCaret)transcriptWindow.getCaret();
+        caret.setUpdatePolicy(DefaultCaret.NEVER_UPDATE);
         splitPane = new JSplitPane();
         packetIDList = new ArrayList<String>();
         notificationLabel = new JLabel();
@@ -245,6 +248,7 @@
 
         // For the first 5*150ms we wait for transcript to load and move
         // scrollpane to max postion if size of scrollpane changed
+        /*
         textScroller.getVerticalScrollBar().addAdjustmentListener(new AdjustmentListener() {
 
             private boolean scrollAtStart = false;
@@ -284,8 +288,8 @@
                 }
             }
         });
+        */
 
-
         // Speed up scrolling. It was way too slow.
         textScroller.getVerticalScrollBar().setBlockIncrement(200);
         textScroller.getVerticalScrollBar().setUnitIncrement(20);
@@ -569,6 +573,7 @@
         newMessage.setProperty("date", new Date());
 
         transcript.add(newMessage);
+        //transcriptWindow.setCaretPosition(0);
 
         // Add current date if this is the current agent
         if (updateDate && transcriptWindow.getLastUpdated() != null) {
@@ -594,7 +599,7 @@
         newMessage.setFrom(from);
         newMessage.setBody(body);
         newMessage.setProperty("date", date);
-        transcript.add(newMessage);
+        transcript.add(newMessage);        
     }
 
     /**
@@ -605,16 +610,29 @@
             return;
         }
 
+        //final JScrollBar scrollBar = textScroller.getVerticalScrollBar();
+        //int maxValue = scrollBar.getMaximum();
+        //int currentValue = scrollBar.getValue();
         int lengthOfChat = transcriptWindow.getDocument().getLength();
-        transcriptWindow.setCaretPosition(lengthOfChat);
+        /*
+        if ((maxValue - currentValue) <= 100) {
+            transcriptWindow.setCaretPosition(lengthOfChat);
+        }
+        */
 
         try {
             final JScrollBar scrollBar = textScroller.getVerticalScrollBar();
             EventQueue.invokeLater(new Runnable() {
 
                 @Override
-                public void run() {
-                    scrollBar.setValue(scrollBar.getMaximum());
+                public void run() {                    
+                    int maxValue = scrollBar.getMaximum();
+                    int currentValue = scrollBar.getValue();
+                    /*
+                    if ((maxValue - currentValue) <= 100) {
+                        scrollBar.setValue(maxValue);
+                    }
+                    */
                 }
             });