I managed to install the Dynamics 365 Developer Toolkit in Visual Studio 2019 (Enterprise edition).

To do this I have changed some version numbers in extension.vsixmanifest before I could install it (this method can be found on the internet at several locations).

It works fine. However every time the solution loads,  it adds one more section to the solution file so that there are many sections like this one:

 GlobalSection(CRMSolutionProperties) = preSolution
  SolutionIsBoundToCRM = True

which is annoying because after the solution is loaded,t is also displaying an error message:

One or more projects in the solution were not loaded correctly.

Please see the Output Window for details.

in the output window it shows: 

Some of the properties associated with the solution could not be read.

How can I get rid of this annoying behavior?