can not zoom with double finger tap

[GoogleCodeExporter]

What steps will reproduce the problem?
1.
2.
3.

What is the expected output? What do you see instead?
zoom in with double finger tap; no reaction.

What version of the product are you using? On what operating system?
latest

Please provide any additional information below.

Original issue reported on code.google.com by lijuan...@gmail.com on 17 Oct 2011 at 7:45

[GoogleCodeExporter]

I meant to say: double-tap with one finger. I.e. tap-tap, not tap with two 
fingers at the same time.

Double-tap to zoom works only in the "Fountain pen", "Pencil", and "Move/Zoom" 
mode. In "Erase" mode, it erases. Twice.

Original comment by vbraun.n...@gmail.com on 18 Oct 2011 at 8:19