Reference for from-outcome element:
The "from-outcome" element contains a logical outcome string returned by the execution of an application
action method selected via an "actionRef" property (or a literal value specified by an "action" property) of a
UICommand component. If specified, this rule will be relevant only if the outcome value matches this element's
value. If not specified, this rule will be relevant if the outcome value is non-null or, if the "if" element is present,
will be relevant for any outcome value, with the assumption that the condition specified in the "if" element
ultimately determines if this rule is a match.
So you have to use non-null outcome or add 'if' element