- gave the drag column a proper 'image' representation

- constrained the drags y coordinates
- made sure a drag is never out of bounds

AppKit/CPTableHeaderView.j

@@ -349,15 +349,18 @@ var _CPTableColumnHeaderViewStringValueKey = @"_CPTableColumnHeaderViewStringVal
         CPLog.debug(@"start drag");
         
         var tableColumn = [[[self tableView] tableColumns] objectAtIndex:aColumnIndex],
-            columnRect = [self headerRectOfColumn:aColumnIndex],
-            // offset = CPSizeMake(_mouseDownLocation.x - aPoint.x, _mouseDownLocation.y);
+            columnRect = [self headerRectOfColumn:aColumnIndex];
         
-        var frame = CPRectMake(0.0, 0.0, [tableColumn width], CPRectGetHeight([[self tableView] bounds])),
-            view = [[CPView alloc] initWithFrame:frame];
-            
-        [view setBackgroundColor:[CPColor greenColor]];
+        var offset = CPPointMakeZero(),
+            view = [[self tableView] dragViewForTableColumns:[tableColumn] event:[CPApp currentEvent] offset:offset],
+            viewLocation = CPPointMakeZero();
         
-        [self dragView:view at:aPoint offset:CPSizeMake(0.0, 0.0) event:[CPApp currentEvent] 
+        viewLocation.x = ( CPRectGetMinX(columnRect) + offset.x ) + ( aPoint.x - _mouseDownLocation.x );
+        viewLocation.y = CPRectGetMinY(columnRect) + offset.y;
+        
+        [view setAlphaValue:0.7];
+        
+        [self dragView:view at:viewLocation offset:CPSizeMakeZero() event:[CPApp currentEvent] 
             pasteboard:[CPPasteboard pasteboardWithName:CPDragPboard] source:self slideBack:YES];
             
         return NO;
@@ -366,10 +369,33 @@ var _CPTableColumnHeaderViewStringValueKey = @"_CPTableColumnHeaderViewStringVal
     return YES;
 }
 
+- (void)_constrainDragView:(CPView)theDragView at:(CPPoint)aPoint
+{
+    var tableColumns = [[self tableView] tableColumns],
+        lastColumnRect = [self headerRectOfColumn:[tableColumns indexOfObjectIdenticalTo:[tableColumns lastObject]]],
+        dragWindow = [theDragView window],
+        frame = [dragWindow frame];
+    
+    // Because the drag window is as wide as the entire tableview, it's start origin is always 0.0
+    // The minimal x coordinate is the minimal dragged table columns negated x value 
+    var minimumX = -(CPRectGetMinX([self headerRectOfColumn:_activeColumn]))
+        maximumX = CPRectGetMinX(lastColumnRect);
+        
+    // This effectively clamps the value between the minimal and maximum
+    // frame.origin.x = MAX(minimumX, MIN(CPRectGetMinX(frame), maximumX));
+    
+    // Make sure the column cannot move vertically
+    frame.origin.y = CPRectGetMinY([self convertRect:lastColumnRect toView:nil]);
+    
+    [dragWindow setFrame:frame];
+}
+
 - (void)draggedView:(CPView)aView movedTo:(CPPoint)aPoint
 {
+    [self _constrainDragView:aView at:aPoint];
+    
     var hoveredColumn = [self columnAtPoint:aPoint],
-    if (_activeColumn === hoveredColumn)
+    if (hoveredColumn === -1 || _activeColumn === hoveredColumn)
         return;
         
     var columnRect = [self headerRectOfColumn:hoveredColumn],

AppKit/CPTableView.j

@@ -1803,7 +1803,7 @@ CPTableViewFirstColumnOnlyAutoresizingStyle = 5;
     return [[CPImage alloc] initWithContentsOfFile:@"Frameworks/AppKit/Resources/GenericFile.png" size:CGSizeMake(32,32)];
 }
 
-- (CPView)dragViewForRowsWithIndexes:(CPIndexSet)theDraggedRows tableColumns:(CPArray)theTableColumns event:(CPEvent)theDragEvent offset:(CPPoint)dragViewOffset
+- (CPView)dragViewForRowsWithIndexes:(CPIndexSet)theDraggedRows tableColumns:(CPArray)theTableColumns event:(CPEvent)theDragEvent offset:(CPPointPointer)dragViewOffset
 {
     var bounds = [self bounds],
         view = [[CPView alloc] initWithFrame:bounds];
@@ -1839,6 +1839,57 @@ CPTableViewFirstColumnOnlyAutoresizingStyle = 5;
     return view;
 }
 
+- (CPView)dragViewForTableColumns:(CPArray)theTableColumns event:(CPEvent)theDragEvent offset:(CPPointPointer)theDragViewOffset
+{
+    var bounds = CPRectMake(0.0, 0.0, 0.0, CPRectGetHeight([self bounds]) + 23.0);
+        index = [theTableColumns count],
+        dragView = [[CPView alloc] initWithFrame:CPRectMakeZero()];
+    
+    // Fetch all the data views for the columns and visible rows
+    // After that copy these add them to a transparent drag view and use that drag view 
+    // to make it appear we are dragging images of those rows (as you would do in regular Cocoa)
+    while (index--)
+    {
+        // Get the tablecolumn and create a rect with it's width so we can use CPRectUnion 
+        // to determine the end result
+        var tableColumn = [theTableColumns objectAtIndex:index],
+            columnIndex = [[self tableColumns] indexOfObjectIdenticalTo:tableColumn];
+            columnRect = [self rectOfColumn:columnIndex],
+            headerView = [tableColumn headerView];
+        
+        // Add the column header view
+        columnHeaderView = [[_CPTableColumnHeaderView alloc] initWithFrame:[headerView frame]];
+        [columnHeaderView setStringValue:[headerView stringValue]];
+        [columnHeaderView setThemeState:[headerView themeState]];
+        [dragView addSubview:columnHeaderView];
+            
+        bounds = CPRectUnion(bounds, columnRect);
+        
+        row = [_exposedRows firstIndex];
+        while (row !== CPNotFound)
+        {
+            var dataView = [self _newDataViewForRow:row tableColumn:tableColumn],
+                dataViewFrame = [self frameOfDataViewAtColumn:columnIndex row:row];
+                
+            // Offset by table header height to make room for the table header
+            dataViewFrame.origin.y += 23.0;
+            [dataView setFrame:dataViewFrame];
+            
+            [dataView setObjectValue:[self _objectValueForTableColumn:tableColumn row:row]];
+            [dragView addSubview:dataView];
+            
+            row = [_exposedRows indexGreaterThanIndex:row];
+        }
+    }
+    
+    // The columns are placed in the drag window at their original locations resulting in the dragged column
+    // being of when started the drag, we compensate for this by offseting the drag window by the x coordinate of the column
+    theDragViewOffset.x -= columnRect.origin.x;
+    [dragView setFrame:bounds];
+    
+    return dragView;
+}
+
 - (void)setDraggingSourceOperationMask:(CPDragOperation)mask forLocal:(BOOL)isLocal
 {
     //ignoral local for the time being since only one capp app can run at a time...