The Vertex grip has 3 edit modes:

Moving the vertex of a window opening on a freeform space surface

Removing the vertex of a window opening on a freeform space surface

Offsetting the edges of a window opening on a freeform space surface
| If you want to… | Then… |
|---|---|
| move the vertex | move the vertex to the desired location, and click; or enter a value, and press Enter. |
| remove the vertex | press Ctrl to switch to the Remove Vertex edit mode, and click to confirm the removal. |
| move the vertex and the adjacent edges | press Ctrl twice to switch to the Offset Edges edit mode. Move the vertex to the desired location, and click; or enter a value, and press Enter. |