Some imported namespaces have a disabled (greyed) check mark
Using VS Community 2022, I have a VB Windows Forms Project. In Project, Properties, References, I see about a dozen namespaces with a check mark indicating they are imported into my project. So far so good.
Three of them (System.Drawing, System.Windows.Forms, and System.Math) are checked with an enabled check mark meaning I can uncheck them. The rest have a disabled check mark (greyed out) meaning I can't uncheck them.
This appears to be a difference between VS 2019 (check marks always enabled) and VS 2022 (some enabled, some not). I would like to trim my namespace imports to a minimum, and I don't mind fully qualifying rarely used names. So how do I remove an import that VS has added but won't let me remove?