
Middle (trackball) panel, lower right button on the Advanced Panel 2 is the "Enable" button. Hit it once, it disables the selected node(s). Hit it again, and it enables the selected node(s). This is covered in the v17 manual starting on page 2909. After a few days, I don't even look down to hit this button -- it's pretty natural to find and select, and I use it at least 100 times in every session.
I can't say enough about how logical and well-designed most of the Advanced Panel 2 is. Though I'm hoping for the swift return of "Lift Keyframe," which we don't have yet.