ShowWindow has wrong P/Invoke signature

[Ron2]

In WeifenLuo.WinFormsUI.Docking.NativeMethods, there's this DllImport:

    [DllImport("User32.dll", CharSet=CharSet.Auto)]
    public static extern int ShowWindow(IntPtr hWnd, short cmdShow);

It should use an 'int' instead of a 'short':

    [DllImport("User32.dll", CharSet=CharSet.Auto)]
    public static extern int ShowWindow(IntPtr hWnd, int cmdShow);

Here are some references of the signature of this Win32 function:
http://msdn.microsoft.com/en-us/library/windows/desktop/ms633548(v=vs.85).aspx
http://www.pinvoke.net/default.aspx/user32.showwindow

We discovered that in Visual Studio 2010, with .Net Framework 4 and AnyCPU platform (on a 64-bit computer) that the Visible property on DragForm was not getting set to 'true', which would prevent those docking indicators from showing and the dragged window from showing. The reason this was happening is that the Win32.ShowWindowStyles.SW_SHOWNOACTIVATE constant of 4 is being put in just the low 16-bits of a register, but there's potentially garbage in the upper 16 bits. We think that on the native side, the full 32 bits is read from the register which causes the flags value to be mangled.

This sounds like the cause of these bugs, too:
#46
#48

[lextm]

Thanks for sharing the details. Your investigation is very helpful and the root cause has been found.

DPS no longer uses ShowWindow call, so we won't need to fix the PInvoke signature now.