How to solve the double screen problem?

[ygy]

Hi,I want to make a control.It is made of a label(show the data) ,a
image(as button) and a trackbar(change the label value).When i click the
image,the trackbar show under the label.My control is like the
numericUpDown,and i add a image button ,click the button,show the trackbar.I
can use the trackbar to change the value of the label.I use the code to
confirm the location of the trackbar:
(The TrackFormCtrl is a form class which contains a trackbar.)

trackForm = new TrackFormCtrl();

int X1=this.Parent.PointToScreen(this.Location).X;
int W1=Screen.FromControl(this).WorkingArea.Width;
trackForm.Location = this.Parent.PointToScreen(new Point(this.Left,
this.Bottom));

if (X1+trackForm.Width>W1)
trackForm.Location = new Point(W1 - trackForm.Width - 5,
trackForm.Location.Y);
When I use double screen,and drag the label and the image button from the
first screen to the second screen,click the image button,but the trackbar
show in the origin screen.I need the trackbar showing in the screen under
the label.How should i do?
Thank you!