How do you change the color of the button?

// ScriptUI graphics update issue

// resource string

var winRes = "dialog {  \
text: 'ScriptUI Graphics test',  \
margins: 15, \
alignChildren: 'row', \
\
    canvas: Panel {  \
        preferredSize: [100, 100], \
        properties: {borderStyle: 'black'} , \
    tempButton: Button { text: 'Examle'}, \
    }, \
    buttonsGroup: Group{ \
        cancelButton: Button { text: 'Cancel', properties:{name:'cancel'} }, \
        tryButton: Button { text: 'Try', properties:{name:'try'},size: [40,24], alignment:['right', 'center'] }, \
          }, \
}" 

// Window

var win = new Window(winRes);

// define the graphic property

win.canvas.graphics.backgroundColor = win.canvas.graphics.newBrush (win.canvas.graphics.BrushType.SOLID_COLOR, [1,0,0],1);

g = win.canvas.tempButton.graphics;
g.foregrounColor = g.newPen (g.PenType.SOLID_COLOR, [0,1,0],1);
win.canvas.tempButton.notify("onDraw");

win.buttonsGroup.tryButton.onClick = function() { // change the graphic background property by click on Button [try]

win.canvas.graphics.backgroundColor = win.canvas.graphics.newBrush (win.canvas.graphics.BrushType.SOLID_COLOR, [0,0,1],1);

}

win.show()

how do you change the color of the button «Examle» ?