Question

I have a tabcontrol with tab items. I would like to open a specific tab in its own window when an user “tears” it off the tab control. I know what to do in terms of creating the window and moving the tab item into that window.

But, I can’t seem to figure out how to keep the window under the mouse, after creating, when it is torn off; so the user interaction is seamless.

I have this in the tabitem’s code:

 protected override void OnPreviewMouseMove(MouseEventArgs e)
        {
            base.OnPreviewMouseMove(e);
            if(e.LeftButton == MouseButtonState.Pressed && _startPoint != null)
            {
                Point position = e.GetPosition(null);

                if (Math.Abs(position.Y - _startPoint.Value.Y) > SystemParameters.MinimumVerticalDragDistance)
                {
                    Point cursor = Utils.GetCursorPosition();
                    var w = new AttachableWindow(){WindowStartupLocation = WindowStartupLocation.Manual, Left = cursor.X, Top=cursor.Y};
                    w.Show();
                    _startPoint = null;
                    e.Handled = true;
                }
            }
        }

Answer 1

Use DragMove method to get the window to move:

w.Loaded += (sender, args) =>
                        {
                            (sender as Window).DragMove();
                        };

Edit: Be careful that doing this in the loaded event can cause the window to render partially. I think the activated event is a better choice.