I find that the lower edges of the buttons in my optionalButtonPane are 
hidden. Doing this sets them to look right:

Preferences setParameter: #defaultButtonPaneHeight to: 30

There are two places where the preference is set to 25 if absent like this 
(in CodeHolder; there's an identical one in FileList class):

defaultButtonPaneHeight
	"Answer the user's preferred default height for new button panes."
	^ Preferences parameterAt: #defaultButtonPaneHeight ifAbsentPut: [25]

Now, it seems to me that instead of setting the parameter, we should just use 
the default. Perhaps this would be better:

defaultButtonPaneHeight
	"Answer the user's preferred default height for new button panes."
	^ Preferences parameterAt: #defaultButtonPaneHeight ifAbsent: [30]

-- 
Ned Konz
currently: Stanwood, WA
email:     ned at bike-nomad.com
homepage:  http://bike-nomad.com