[LC] 8.1.5 The output Element (+)

http://www.w3.org/TR/xforms11/#ui-output

"It is used to display values from the instance, and is treated as
display:inline for purposes of layout."

This should say that its default styling is display:inline.

Note that other controls do not have this information, which gets in
the way of interoperability, since different implementations may have
different defaults for controls.

Similarly, the read-only, relevant, invalid, and required properties
should be required to have some default value (I have used at least
one implementation which required a style sheet before invalid values
were visible.)