Reference line layer order

[Sergiy Radyakin]

Dear All, is there any way to control the sequence order of drawing a graph (aka z-order), so that the reference line is placed on top of the graph?
Consider the following example, quite naturally one would expect the line to be on top of the area.

I have already tried to place an invisible scatter on top and add a refline there, but it seems that Stata first merges all the layers and then sinks the reflines to the very bottom of the z-order.

I am obviously trying to avoid manual calculation of the coordinates like: twoway area pc n || scatteri 0 30 500000 30, lpattern(--) recast(line)

Any workarounds for this?

Thank you, Sergiy Radyakin

clear all
sysuse auto
sort price, stable
generate n=_n
generate pc=price in 1
replace pc=price + pc[_n-1] in 2/L
twoway area pc n, xline(30, lpattern(--))

[Andrew Musau]

tw dropline provides one workaround.

clear all
sysuse auto
sort price, stable
generate n=_n
generate pc=price in 1
replace pc=price + pc[_n-1] in 2/L
gen xline=30
twoway (area pc n, leg(off)) (dropline pc xline, lpattern(--) ///
mcolor(none) lcolor(red)), xline(30, lpattern(--) lcolor(red))

[Sergiy Radyakin]

Thank you very much! This is helpful.
At first I thought that the red part can be simplified somewhat, but upon experimenting see that both parts are necessary.
Very clever!