### solving equation involving absolute values

Hello

I am newbie to sagemath. I have windows 8 and sage version is 6.4.1. I am running it inside virtualbox.
I was reading some thing about solving equations on sage website at
http://www.sagemath.org/doc/reference/calculus/sage/symbolic/relation.html

At one point author is trying to demonstrate the use of optional keywords for the "solve"
He is solving equation

solve(abs(1-abs(1-x)) == 10, x)

When evaluated this gives

[abs(abs(x - 1) - 1) == 10]

But when the input is modified a little as

solve(abs(1-abs(1-x)) == 10, x, to_poly_solve=True)

sage gives correct result as [x == -10, x == 12]

So why does it not work in the first case ? I didn't understand this use of keyword to_poly_solve.

I tried to post this question on sage-support but for some reason my posted question doesn't seem to appear there.

Please help
sundar