I had this problem with PixelGetColor not giving me the same HEX Color as the AU3Info Tool and searched every were with no luck then had a OH DA moment LoL.
The problem is that the
"PixelGetColor ($mouseX[0], $mouseY[1])"
is looking rite at the very tip of the mouse pointer not under it. So you have to set a -3 after the [0] and [1].
"PixelGetColor ($mouseX[0] -3, $mouseY[1] -3)"
to make it search next to the pointer not on the pointer. You may have to adjust this a bit for your display but you should not have to go more then -5. -3 seems to work best for me.
Example.au3
#include <EditConstants.au3>
#include <GUIConstantsEx.au3>
#include <StaticConstants.au3>
#include <WindowsConstants.au3>
$Form1 = GUICreate("Form1", 141, 127, 276, 231)
$Input1 = GUICtrlCreateInput("", 8, 8, 121, 21)
$Label1 = GUICtrlCreateLabel("Press or Hold F1 to get Hex color at Mouse X -3, Y-3 Pos,", 8, 40, 124, 73)
GUISetState(@SW_SHOW)
HotKeySet("{f1}","MousePos")
Func MousePos()
$aPos = MouseGetPos()
$PGC = PixelGetColor($aPos[0] -3, $aPos[1] -3)
GUICtrlSetData($Input1, "0x" & Hex($PGC, 6))
EndFunc
While 1
$nMsg = GUIGetMsg()
Switch $nMsg
Case $GUI_EVENT_CLOSE
Exit
EndSwitch
WEnd