well, the Grasshopper script is being computed here to enable the 3D/Plan/Preview settings (and also on the Parameters settings), so you may notice a slow performance for complex definitions. We will see if we can improve this.
I have noticed that when a gh style has some or more boolean operations, surface trims etc, the lag happens both in import and when previewing the style, similar to what would happen to a normal gh definition and its viewport preview when making changes.