I downloaded the DropGC to use in SketchUp Make, but I cannot find the Extensions category under the Windows drop-down menu. Where am I supposed to find it?
Did you access the Extension Warehouse through SketchUp directly? If not, you should. go to Window>Extension Warehouse, search for DropGC and click Install. It’ll be installed automatically.
If you read the usage instructions for it you’ll see it is found in the Context menu.