diff --git a/ui/jquery.ui.autocomplete.js b/ui/jquery.ui.autocomplete.js
index 5dda7d970..4e528dce4 100644
--- a/ui/jquery.ui.autocomplete.js
+++ b/ui/jquery.ui.autocomplete.js
@@ -452,7 +452,9 @@ $.widget( "ui.autocomplete", {
 	_resizeMenu: function() {
 		var ul = this.menu.element;
 		ul.outerWidth( Math.max(
-			ul.width( "" ).outerWidth(),
+			// Firefox wraps long text (possibly a rounding bug)
+			// so we add 1px to avoid the wrapping (#7513)
+			ul.width( "" ).outerWidth() + 1,
 			this.element.outerWidth()
 		) );
 	},