When using LegendLayout->"Row", with a lengthy row, I get line breaks. This would seemed logic if it was confined by another structure. But if happens even when there's no "confinement":
LineLegend[{Blue, Orange, Green}, {"this is a big test",
"this is a big test", "this is a big test"}, LegendLayout -> "Row"]

How can I change the ItemSize/ImageSize of the Legend?
(should this behavior be reported?)