Incorrect output path in project properties (.NET Framework)

[D0tNet4Fun]

Steps to reproduce:

1. Open Visual Studio 2017.
2. Create a new project of type Class Library (.NET Framework).
3. Go to project properties > Build

Expected results: the Output Path should be bin\Debug\, relative to the project's directory.

Actual results: the Output Path is absolute and starts with the root output path.

[D0tNet4Fun]

The initial assumption was that the new project embedded the root output path in the project file. Wrong, the OutputPath defined in the project file is the default:

  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <OutputPath>bin\Debug\</OutputPath>

I had incorrectly assumed that Visual Studio uses the definition in the project file to fill in the OutputPath textbox in the project properties UI. It looks like what it is used is the property value after MSBuild evaluates it.

[D0tNet4Fun]

This happens for all projects when the extension is used, not just new ones. Visual Studio functionality is not affected by this change though. Users can still set a custom output path in the project properties dialog and this path will be persisted into the project file.