What is a Gripper?
The Gripper is the "command center" for each GeoBar. By right clicking on a GeoBar's gripper you open a menu that gives you a lot of control over the basic operations of that bar.
Where are Grippers?
The main Gripper is located on the left for horizontal GeoBars or on the top for vertical GeoBars.
The 'left gripper' is the main one, but there is actually a very thin right gripper on GeoBars too that can be used to access the Gripper Menu.

Configuring your Grippers
Four unskinned GeoBars, there are 10 different hardcoded gripper styles to choose from. Here is a preview:

Note: The Colored style has the ablility to be more interesting than this screenshot indicates, I didn't realize that I hadn't set the gripper colors to anything more interesting when I made those screenshots.
The gripper is configured from the Gripper Menu, and for unskinned bars the menu should look like this:

This menu is hidden on skinned GeoBars, since it has no effect on bars with skins.
Internal Gripper Style Names
Just a quick warning about gripper style name: The name you see on the menu is probably not the same name used in the KEY_CURRENT_USER\Software\geO\geOShell\Services\Plugins\GeoBar(#)\Gripper Style registry settings. Most of the internal names are of the developer that added that style, not the name of the style itself. The internal names are as follows:
- Windows - windows
- Colored - supernull1
- Geo - r3
- Standard - standard
- Blank - blank
- R4: 2 - daemon1
- R4: 3 - daemon2
- R4: 4 - daemon3
- R4: 5 - daemon4
- Thin - eik