How does Path mapping work in ReSharper?
===

I have been struggling to find a good detailed explanation for that anywhere. So I have a project (destined to be deployed to SharePoint) which is organized as follows:

    MyProject
        12
            TEMPLATE
                CONTROLTEMPLATES
                FEATURES
                LAYOUTS
                    Images
                        MyImage.png

In a css file somewhere I have the following line:

    .myClass { background: url(/_Layouts/Images/MyImage.png); }

Obviously the whole url comes out red and I have a ReSharper error stating:

    Path C:\MySolutionFolder\MyProject\_Layouts\Images\MyImage.png not found

So at no point I expect ReSharper to understand anything about SharePoint, I just want to understand how to map folders.

So I went to the project's properties, and created a new mapping:

*Substitute* **/_layouts** with **C:\MySolutionFolder\MyProject\12\TEMPLATE\LAYOUTS**

That does not seem to do anything, so I tried playing around, and the only thing I found to do *something* is:

*Substitute* **_Layouts** with **C:\MySolutionFolder\MyProject\12\TEMPLATE\LAYOUTS**

Instead of the previous error, I now only have the *_Layouts* part of the url in red, and a new ReSharper error:

    Symbol '_Layouts' doesn't exist in CSS 3.0

Note that it seems wrong to put this path mapping without the initial slash, because it feels like it would replace the word '_layouts' in any position in the path, when it should only be replaced at the root path of the site.

And also, the fact that the mapping changes the error seems to be case sensitive, something I do not understand for a url path mapping (urls are not case sensitive are they?).

Also, using Ignore instead of Substitute does not make the error disappear. It seems the only way there is is to disable the error, which IMO is really a bad thing.

Behaviour has been reproduced on 6.1 and 7.0.

And if the path mapping is not what I think it is, is there any way around this? A plugin, for instance?