You can find the Rhino 7 version in Shaper3D Gadgets.
This is the first release of TopMostViewport to Rhino 5.
This utility exposes one command: _TopMostViewport
It create a top most viewport in your Rhino window. The mosttop viewport can floating on Grasshopper canvas when you are working in Grasshopper.
- In Rhino, choose Tools > Options > Plug-ins > Install. Select the rhp file.
Topmost viewport floating on Grasshopper