palette color help

[pmackay]

hi, i am using qb64 pe... I am trying to change a pallete color of one pixel to another (copy a pixel using point(x,y)

i have a screen mode of (512,256 in 32) screen

screen  _newimage (512,256,32)

// old point

a=point (oldx,oldy)

// new color

b=point (newx,newy)
_palletcolor a,b

i am reading the pallet color from a palette image i made with colors... it is a pop up so i click the old color. window pops up. i click the new color from pallet and it changes to new color

help please. i is only changing to blue....
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        IF E = -1 THEN
            PA! = POINT(_MOUSEX, _MOUSEY)
            _PUTIMAGE (104, 80), GPALETTE,: _DISPLAY
            DO
                A = _MOUSEINPUT
                IF _MOUSEBUTTON(1) = -1 THEN PB! = POINT(_MOUSEX, _MOUSEY): _PALETTECOLOR PA!, PB!: _DISPLAY: EXIT DO
                LOCATE 1, 1: PRINT _MOUSEX, _MOUSEY, A: _DISPLAY
            LOOP
        END IF