Resizing the Shapes window

[Mark Tangard]

When the Shapes window (the stencil repository at the left, I mean) is
docked, mousing over its right border gives the usual two-headed arrow
that means you can resize the window by dragging.

But it won't resize. Is there something I'm missing? Given the small
monitor here I'd like to claim as much space for the diagram but still
have the shapes visible.

Visio Pro 2003, WinXP.

Thanks.