color of a Drag Marker?

[#1]

How can i change the color of a Drag marker?

with a black & white background the black circles are hard to see:

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Names Default To Here( 1 );

img = New Image( "https://www.nasa.gov/sites/default/files/styles/full_width_feature/public/thumbnails/image/hubble_leda48062_potw2302a.jpg" );

win = New Window( "marker",
V List Box (Text Box("black marker hardly visible"),
		g = Graph Box (
			Framesize( 600, 300 ),
			X Scale( 0, 1000 ),
			Y Scale( 0, 500 ), 
			Marker Size( 30 );
			Color State( {0, 1, 1} );
			Drag Marker( [500], [200], showpoints = 0, showpoints = 1 );
		) )

);

imgBox = win[framebox( 1 )];
imgBox << AddImage( Image( img ), bounds( Left( 0 ), Right( 1000 ), top( 500 ), bottom( 0 ) ) );
imgSeg = imgBox << FindSeg( PictSeg( 1 ) );
imgSeg << lock( 1 );

[#2]

You can't.

[#3 · Accepted solution]

Ouch!
why?

here is the wish:

Drag Markers: option to adjust the color (and shape?)