Is a hidden reference breaking my Microsoft Band project build?

Question

While trying to find libraries that would provide my Microsoft Band UWP app with the features I want, I must have done something bad: my project will no longer build. The two error messages are:

Severity Code Description Project File Line Suppression State Error Type universe cannot resolve assembly: System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089. BandScan.Windows

Severity Code Description Project File Line Suppression State Error Cannot resolve Assembly or Windows Metadata file 'System.Windows.Forms.dll' BandScan.Windows C:\Users\allen\Documents\Visual Studio 2015\Projects\UABlankApp2\UABlankApp2\UABlankApp2.Windows\BandScan.Windows.csproj

This is a UWP project in Visual Studio 2015 Community Edition targeting Windows 8.1, with the Nuget Microsoft Band package. I don't know why it is referring to System.Windows.Forms.dll but it may have crept in when I was trying to find a way to incorporate a namespace that supports speech recognition. Now I have a 4,000-line project that mysteriously refuses to build.

Is there a way to find and remove reference to System.Windows.Forms.dll?

Is there anything else I should try?