I'm trying to figure out how to create irregular polygons in Visio 2010. The instructions I've found are pretty simple:

1. Select the line tool.
2. Click at the first vertex, drag to the second vertex, and release.
3. Click and drag to the third vertex and release, and so on.
4. Click and drag from the last vertex to the first vertex.

This is admirably clear, but it only works about a third of the time. The rest of the time the figure appears closed, but isn't. This is even though the "snap to geometry" balloon appears before I release the mouse button at the end of the process.

I'm reduced to drawing and deleting the polygon over and over until it magically closes.

Does anyone know how to make this process behave?