VS 2008 Screen.GetWorkingArea And PointToScreen - Dual Screen ?

I have a button btnRegEx that when pressed shows a ContextMenuStrip, similar to the '>' button in the Find/Replace dialog in Visual Studio when you are using Regular Expressions. I have a ContextMenuStrip cms which I show using its Show(x,y) method.

At first I was simply setting x and y (the location of the ContextMenuStrip) to some point next to the button, but I noticed that when the button is close to the edge of the screen it goes off screen. I wanted to prevent that so I built some logic into the x-y calculation. When the ContextMenuStrip width is larger than the 'remaining space left' I simply show it more to the left. Same for its Height of course. I am using the Screen.GetWorkingArea(point) method to determine the 'remaining space left'. As I understand it, it returns the working area closest to the point you specify (to which I pass the button's location).

As long as I stay on my first monitor, it is all working perfectly fine. The problem occurs when I move the form to my second monitor. The contextmenustrip is still showing on the first monitor for some reason...

Here is the code I am using:

vb.net Private Sub btnRegEx_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRegEx.Click
Dim p As Point = PointToScreen(New Point(btnRegEx.Left, btnRegEx.Top))
Dim x, y As Integer

[CODE]...

I have noticed that when I click the button when the form is on the second monitor, the buttons location (p) is calculated with the first monitor's top-left corner as (0,0), even though it is on the second monitor. This way, the GetWorkingArea function returns something like 1280, while the buttons x-location is something like 1700... So, how do I get the buttons coordinate relative to the actual screen it is on, rather than the entire dual monitor screens as a whole?