.Net Reflector not decompiling Unity DLL's when pressing F12

Hi there!

New customer here, so not sure whether or not this worked in earlier versions.

I'm on version 9.2.0.117 VSPro - Visual Studio 2017

We bought this mainly for the purpose of decompiling and potentially debugging the Unity engine, but we've found that It's not really happy doing just that.

When I hit F12 on any other type, it works just fine. It decompiles, and it's happy.
But when hitting F12 on any Unity dll, it opens the "decompiling" window for a split second, and we're left with the window we are used to. (Nothing was decompiled)

However, if I navigate to the type in the via the .Net Reflector Object Browser, it decompiles it just fine. Generating PDF files for the Unity DLL's also went just fine, but didn't fix anything.

GotoDefinition (F12) is enabled of course.

And here are the relevants parts of one of our csproj files. don't know if that is helpful.

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
    <ProjectGuid>{22731B01-1F5D-477A-811C-DF6F1E873A2A}</ProjectGuid>
    <OutputType>Library</OutputType>
    <AppDesignerFolder>Properties</AppDesignerFolder>
    <RootNamespace>Sirenix.Utilities</RootNamespace>
    <AssemblyName>Sirenix.Utilities</AssemblyName>
    <TargetFrameworkVersion>v3.5</TargetFrameworkVersion>
    <FileAlignment>512</FileAlignment>
    <TargetFrameworkProfile>Unity Subset v3.5</TargetFrameworkProfile>
    <ProjectTypeGuids>{E097FAD1-6243-4DAD-9C02-E9B9EFC3FFC1};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <DebugSymbols>true</DebugSymbols>
    <DebugType>pdbonly</DebugType>
    <Optimize>false</Optimize>
    <OutputPath>..\..\Unity Project\Assets\Plugins\Sirenix\Assemblies\</OutputPath>
    <DefineConstants>UNITY_5_3_OR_NEWER;UNITY_5_3;DEBUG;CAN_EMIT;UNITY_EDITOR;ODIN_INSPECTOR;SIRENIX_INTERNAL</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
    <DocumentationFile>..\..\Unity Project\Assets\Plugins\Sirenix\Assemblies\Sirenix.Utilities.xml</DocumentationFile>
    <LangVersion>4</LangVersion>
    <NoWarn>CS1723, CS1723, CS1574, CS1584, CS1658</NoWarn>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
    <DebugType>pdbonly</DebugType>
    <Optimize>true</Optimize>
    <OutputPath>..\..\Unity Project\Assets\Plugins\Sirenix\Assemblies\</OutputPath>
    <DefineConstants>UNITY_5_3_OR_NEWER;UNITY_5_3;DEBUG;CAN_EMIT;UNITY_EDITOR;ODIN_INSPECTOR;SIRENIX_INTERNAL</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
    <DebugSymbols>true</DebugSymbols>
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="System" />
    <Reference Include="UnityEditor, Version=0.0.0.0, Culture=neutral, processorArchitecture=MSIL">
      <SpecificVersion>False</SpecificVersion>
      <HintPath>..\Libraries\UnityEditor.dll</HintPath>
      <Private>False</Private>
    </Reference>
    <Reference Include="UnityEngine">
      <HintPath>..\Libraries\UnityEngine.dll</HintPath>
      <Private>False</Private>
    </Reference>
  </ItemGroup>
</Project>