Workspace switcher crashes at 20

[Alan J. Gagne]

> The backtrace disagrees with you. It aborts due to an assertion that
> the workspace name isn't NULL. No indication of "not enough memory"
> or heavy memory usage when enabling 20 workspaces.
     I ran into this issue when increasing from 14 to 18 workspaces.
You could switch between spaces with the mouse but as soon as you
use ctl+alt+arrows metacity would crash with the assertion failure.

I found a way to get around  this by naming the workspaces.
Currently I have 20 workspaces configured.

Alan