Custom Window Resize And Relocate

How would I re-size the window @ a point relative to its parent location and size. I am using code from Make an unowned window's parent to my form, to be able to set a windows parent to panel1.

Dim proc As Process
' Start the process
proc = Process.Start("C:UsersDmitryAppDataRoamingSpotifyspotify.exe")
proc.WaitForInputIdle()
Dim tmp_hWnd As IntPtr
[Code] .....

This works on most windows except for ones that are customized. Maximizing the window will maximize the window to bounds of the actual screen bounds instead of the panel1 bounds. Code works fine with normal windows but not with this one. (Spotify Window.)
SendMessage(proc.MainWindowHandle, 274, 61488, 0)