An error in the fsproj file prevents it from opening

I created a new project in Visual Studio 2013 using F# ASP.NET MVC 5 and Web API 2, available here , but I got mine on Nuget.

The template sets the directory Contentfor CSS files, and the other Scriptsfor JavaScript files. In each of these directories, I created subdirectories and put files in them. Now, when I try to reopen the project after closing it, I get the following error:

The project 'PROJECTNAME.fsproj' could not be opened because opening it would cause a folder to be rendered multiple times in the solution explorer. One such problematic item is'Content\Widgets\jQueryIO\v_1_10_4\Lightness\jquery-ui-1.10.4.custom.min.css'. To open this project in Visual Studio, first edit the project file and fix the problem.

The lines in the file fsprojin question are shown below:

    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\jquery-ui-1.10.4.custom.min.css" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\animated-overlay.gif" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-bg_diagonals-thick_18_b81900_40x40.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-bg_diagonals-thick_20_666666_40x40.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-bg_flat_10_000000_40x100.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-bg_glass_100_f6f6f6_1x400.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-bg_glass_100_fdf5ce_1x400.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-bg_glass_65_ffffff_1x400.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-bg_gloss-wave_35_f6a828_500x100.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-bg_highlight-soft_100_eeeeee_1x100.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-bg_highlight-soft_75_ffe45c_1x100.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-icons_222222_256x240.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-icons_228ef1_256x240.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-icons_ef8c08_256x240.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-icons_ffd27a_256x240.png" />
    <None Include="Content\Widgets\jQueryUI\v_1_10_4\Lightness\images\ui-icons_ffffff_256x240.png" />

The only link to the problem I could find is the following link:

http://cs.hubfs.net/topic/None/60049

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