This is an issue in VS 2019 which is caused by blocking any extension from synchronously autoloading since 16.1, see: https://devblogs.microsoft.com/visualstudio/updates-to-synchronous-autoload-of-extensions-in-visual-studio-2019/
In V&I this applies to Suggestions (Light Bulb actions - Add File(s) / Add Folder into script) and the References window. Both must be reworked/fixed for VS 2019.
The Suggestions are already done and we are currently working on the References window.
Both will be ready in next V&I release.
Update 27-11-2020: The transparent (blank) controls in References windows are caused by changes in .net DPI awareness: https://blog.jetbrains.com/dotnet/2019/06/11/blank-tool-windows-resharper-visual-studio-2019-net-framework-4-8-per-monitor-dpi-awareness/
Temporary solution is to uncheck Optimize rendering for screens with different pixel densities via Tools | Options, then Environment | General.

Update 2020-11-30: Today we have released an updated version of this tool where we have fixed this issue (it is necessary to reinstall the extension in Visual Studio 2019).
See the details and get latest version from official website: http://visual-installer.com/changelog.html#10410