Unlock gray "handles" (or "Vertices" ?) on a visio shape

[Mit]

Hello:

To Do: I'd like to modify a Visio shape but it seems that the vertices are locked. I attached a picture. I have Visio 2007.

My Steps: In the 'Blocks(Metric)' stencil is visio's "Curved Arrow" shape.
I saved this in my own stencil.
I did a Right click on shape (in the stencil area) and chose "Edit Master"
I was able to change the angle by choosing the yellow handle at the apex of the arrow.
I'd like to make the angle of the arrow head less wide, but upon choosing the pencil and clicking on the shape, it seems that the vertices are locked. They are grey. (see pic)
I did a right click -> Format -> Protection and nothing is selected.
Nothing is grouped.
This seems like it should be easy to do. But I cant' think of anything else to do.
Is it possible to change the vertices?

[Paul Herber]

Open the shape's shapesheet, there is a protection not available from the standard dialog. It's called LockVtxEdit. Turn that off, then you can use the pencil tool.
You might be able to make suitable changes via the shapesheet. Depends.

[Mit]

This worked, and I learned something new!
Thank You.