Disabled checkboxes display incorrectly using Redmond controls theme.

[BenFenner]

System configuration:
Linux Mint 17.1 Rebecca LTS (64-bit)
gtk2-engines 1:2.20.2-3ubuntu1

Steps to reproduce:

Switch the controls (buttons, checkboxes, radio buttons) to the Redmond theme.

Create an HTML document with these contents and open it in a browser (I'm using Pale Moon):

<form>
<input type=checkbox>Active checkbox, unchecked<br>
<input type=checkbox checked="checked">Active checkbox, checked<br>
<input disabled="disabled" type=checkbox>Disabled checkbox, unchecked. (This shows incorrectly as checked.)<br>
<input disabled="disabled" type=checkbox checked="checked">Disabled checkbox, checked<br>
</form>

You should notice that the third checkbox is disabled and not checked per the code, but shows as checked/selected when it should show as unchecked/unselected.
Example:
https://i.imgur.com/XLb8CKc.png

Switching the desktop theme to something else (Mint-X for example) fixes the problem.
Example:
https://i.imgur.com/PoUd6na.png

[BenFenner (ben-fenner)]

This issue causes me troubles every once in a while, and just today it hit me hard...

Has anyone looked at this?
Do I need to include more information?

[BenFenner (ben-fenner)]

Has there been any movement on this?

[BenFenner (ben-fenner)]

This one is probably super easy to fix. Anyone trying to get their feet wet should tackle this one. =D