I have four workspaces, laid out end to end.  I can move (by placing mouse at
screen's edge) from ws1 to ws4 and back again (ws4 - ws1).  However I cannot go
from ws1-ws4, i.e. I cannot place the mouse at the left side of workspace 1 and
end up in workspace 4.  Just to over-describe this: the window manager is
treating my workspaces as a linear chain, not a circular one.  Using the scroll
wheel I have no problem jumping directly from ws1 to ws4, but sliding the mouse
doesn't work.  

This may not be a bug, but rather, how do I inform the window manager to allow
the changing of workspace from 1 to 4 when the mouse is on the left of the
screen (or from ws4 to ws1 when the mouse is on the right side of the ws4 screen).

Reproducible: Always
Steps to Reproduce:
1. Start XFCE with 4 workspaces 
2. Slide mouse to the absolute left of screen
3. workspace will not change

Actual Results:  
the workspace did not change from workspace 1 to workspace 4.

Expected Results:  
The workspace should have gone from 1 to 4.

For what it's worth:
XFCE 4.1.90
XFree86 4.3.0
GTK 2.4