Coordinates of the cursor are shifted and do not reflect displayed image when using Firefox

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Open demo: 
http://svg-edit.googlecode.com/svn/branches/2.6/editor/svg-editor.html
2. Select "pencil tool"
3. Draw something on the paper

What is the expected output? What do you see instead?
Expected: drawing under the mouse
Actual: image was appearing in bottom right corner outside of the paper (the 
shift is equal to exactly width/height of the paper when zoomed to 100% - when 
drawing in left top corner image appears in bottom right)
Same thing happens on other tools and selection tool. When zoomed shift also 
changes but randomly (couldn't see any dependence)
I tried refreshing website - didn't help

In what browser did you experience this problem? (ALL, Firefox, Opera, etc)
Firefox (newest: v. 26.0)

In what version of SVG-edit does the problem occur? (Latest trunk, 2.5.1,
etc)
2.6 (I think newest, demo)

Please provide any additional information below.
Only two add-ons installed:
- adblock (tried disabling, didn't help)
- foxy proxy

I tried different browser: On Chrome works fine.
I tried on different computer with FF: Same bug occurs

Original issue reported on code.google.com by mordotym...@gmail.com on 30 Jan 2014 at 9:18

[GoogleCodeExporter]

This has been fixed in the trunk version of svg-edit: 
https://code.google.com/p/svg-edit/source/detail?r=2524.

View the trunk (latest) demo to see it working correctly: 
http://svg-edit.googlecode.com/svn/trunk/editor/svg-editor.html.

Original comment by breit...@gmail.com on 24 Feb 2014 at 11:36