CanExecute isn't called for DataGrid's SelectedItems property

[SSteve]

A window's DataContext doesn't have its CanExecute method called when there is a RelayCommand with a DataGrid's SelectedItems property as a command parameter. Using MVVMLight, the method is called.

I've attached two versions of the same program, one using CommunityToolkit.MVVM and one using MVVMLight. The CanExecute method for the ProcessMultipleSelectedCommand RelayCommand is called correctly in the MVVMLight version but not the CommunityToolkit.MVVM version. Am I doing something wrong, is this a limitation in CommunityToolkit.MVVM, or is this a bug in CommunityToolkit.MVVM?

SelectedItemsTest.zip
SelectedItemsTestMVVMLight.zip