Newly added cshtml files to RCL (Razor Class Library) are automatically removed in project file

Question

After adding a shared _JstreeSearchInput.cshtml file, I noticed that it coucld not be used by other projects. This was a re-happened problem so after several minutes I re-remembered that these codes in .csprj file of the RCL were the reason:

  <ItemGroup>
    <Content Remove="Views\Shared\_JstreeSearchInput.cshtml" />
  </ItemGroup>

  <ItemGroup>
    <EmbeddedResource Include="Views\Shared\_JstreeSearchInput.cshtml" />
  </ItemGroup> 

These codes come from nowhere but every time I add new .cshtml files, they appear. Deleting them is easy only if I can re-remember it.

So, who added the code? Is there any way to prevent it from happening in the future?

Thanks for any tips.