Button Preferences
The "Buttons" tab contains settings related to HTML Help's toolbar buttons.

Hide/Show
Toggles the navigation pane on and off.
Back
Navigates back to the previously viewed page.
Forward
Navigates forward to the next viewed page. Becomes available after having navigated backwards.
Stop
Stops the current page load operation.
Refresh
Reloads the current page.
Home
Returns the the help file's start page. This is set to the main page of the stored site.
Locate
Finds the current page in the contents list. This is unnececessary if "Auto synch" is selected on the Navigation tab.
Options
Opens the HTML Help Viewer's options menu. The options are not accessible if the Options button is not included.
Prints the current page.
Font
Opens the font selection dialogue so you can select the viewer font.
Next
Jumps to the next topic in the contents pane.
Previous
Jumps to the previous topic in the contents pane.
Help Button
Opens the inline help.