Alt dropper can't be used in Linux

What steps will reproduce the problem?
1. In any Linux distro and most window managers, hold left alt and click on a 
pixel.

What is the expected output? What do you see instead?
Expected output: the colour picker picks the colour I clicked.
What happens instead: default window behaviour is triggered (alt+click/drag is 
used to drag the window around, just like dragging the title bar).

What version of the product are you using? On what operating system?
v0.9.5 on Xubuntu 12.10.

Suggestion:
Allow the Alt-Gr (right alt) and meta (Windows) key to be used for the colour 
dropper too. If one won't work, another likely will. Window dragging behaviour 
isn't triggered with right alt on the window manager I use (Compiz). Or to be 
entirely safe, Shift could be used for this, or the software could try some 
input locking when holding the alt key to prevent the window dragging behaviour?

Original issue reported on code.google.com by VincentB...@gmail.com on 3 Feb 2013 at 1:35

thecocce / aseprite

Alt dropper can't be used in Linux #205