[Jeff]

Add the 2D object to the ortho layer, that's what panels are added to. Then you can set the draw order:

import viz
import vizdlg
import vizact

viz.go()

myPanel = vizdlg.Panel(align=vizdlg.ALIGN_CENTER)
myPanel.addItem(viz.addText('A simple panel'),align=vizdlg.ALIGN_CENTER)
myPanel.addItem(viz.addCheckbox())
myPanel.addItem(viz.addSlider())
myPanel.addItem(viz.addTextbox())
viz.link(viz.CenterCenter,myPanel)

quad = viz.addTexQuad(parent=viz.ORTHO)
quad.texture(viz.addTexture('image2.jpg'))
quad.drawOrder(5)
quad.setScale([200]*3)
viz.link(viz.CenterCenter,quad)

slider = viz.addSlider()
slider.set(1)
slider.setPosition([0.5,0.2,0])

def alphaSlider(pos):
	quad.alpha(pos)

vizact.onslider(slider,alphaSlider)