Hi Rich,
Since I'm to blame for your current predicament 
I'll try to answer your queries.
On Jan 30, 2010, at 10:00 AM, grass-user-request@lists.osgeo.org wrote:
Message: 3
Date: Fri, 29 Jan 2010 14:05:47 -0800 (PST)
From: Rich Shepard <rshepard@appl-ecosys.com>
Subject: [GRASS-user] Working Effectively With wxPython GUI
To: grass-users@lists.osgeo.org
Message-ID:
<alpine.LNX.2.00.1001291358430.13189@salmo.appl-ecosys.com>
Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCIIMichael Barton's convinced me that I need to become as fluent with the
wxPython GUI as I am with d.mon. I'm finding this to be a bit of a
challenge.For example, I have all pertinent raster and vector layers loaded in the
workspace. When I want to see only the r.param.scale output map (raster
named 'morphology') I have to turn other layers on and off before just that
one will display.
Same with d.mon and and d.rast/d.vect--except with d.mon you can't turn layers off and on, you have to recomposite them.
The layer manager acts like a stack of transparent or semi-transparent maps. You can also drag and drop them to rearrange the stacking order.
Yes, I do specify 'zoom to selected map(s)' from the menu.
Haven't figured out why.
The GUI, like d.mon will start up with your default region or whatever region has been set for that mapset. Set the computational region extents to match the display to see the same thing each time you start GRASS (a menu button in the zoom tool section of the display canvas). Zoom to selected map lets you zoom the display to match the extents of the map (like g.region rast=map, except that it only affects the display, not your computations).
When I want to overlay a vector map with fcolor=none, how do I do this
from the list of loaded maps?
Double click on the vector map layer and change fill color to none
If I turn on the 'basin' map, for example, it
has a solid fill and blocks the map underneath it.
Either you have set nulls to be opaque (change for a single map in the map properties or for all maps in configure preferences) or the "fill" has non-null values and should be blocking out what is underneath.
Changing the opacity
level affects the vector lines, not the fill within each polygon.
Yes it does affect the fill unless there is a bug somewhere.
A couple of other hints. There is very good help for the GUI under the GRASS help menu. Also, you can save a workspace and restore it the next session.
Hope this helps
Michael