The Toolbar
What the toolbar buttons are
What the pane buttons do
The traffic light button
The thread button or buttons

What the toolbar buttons are
In the picture below from left to right the toolbar buttons are:-
codepane, register pane, esp stack pane, ebp stack pane, log pane, mmx/fpu register pane (also 3DNow!), xmm register panes (xmm, sse and sse2), traffic light control and thread button.

What the pane buttons do
Use these to make the pane appear or disappear. You can change the position of the panes in the main window by removing them all and then reinstating them in the order of your choice. They re-appear in this order: top left, bottom left, top right, bottom right.

The traffic light button
Use this button to view and control the current action of the threads. For more information see traffic light control.

The thread button or buttons
Each thread has a button. Use these buttons to view the current state of a thread as far as is known to GoBug. For more information see thread buttons