# What is the syntax for selecting multiple layers in an Overlay?

From the documentation:

Overlay[{Subscript[expr, 1],Subscript[expr, 2],...},{i,j,...},s] allows selections to be made and controls to be clicked in Subscript[expr, s].

and an example of selecting one layer:

Overlay[{Slider2D[], Graphics[{Opacity[.2], Disk[]}]}, All, 1]


Does anyone know what the syntax is for cases in which you want controls to be clicked in more than one layer, or all layers?

I have tried:

Overlay[{Slider2D[], Graphics[{Opacity[.2], Disk[]}]}, All, All]


and

Overlay[{Slider2D[], Graphics[{Opacity[.2], Disk[]}]}, All, {1,2}]


without success.

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As far as I'm concerned nothing in the phrasing of the documentation suggests that you should be able to use more than one layer for selections. –  Sjoerd C. de Vries Jun 17 '12 at 7:30
@SjoerdC.deVries I'd agree but sometimes in these situations that reflects inadequate documentation rather than inadequate functionality. –  Mike Honeychurch Jun 17 '12 at 22:40
lol.. Mike, I just tried doing exactly this. –  Amatya Sep 25 '12 at 2:23

I don't think the third argument of Overlay can be used to do what you want. An alternative is to change the active layer dynamically using EventHandler as in
 DynamicModule[{layer = 1},