Dimensions: Reverse a check to avoid potential reflows

Fixes #14979
Closes gh-1560

AUTHORS.txt

@@ -221,4 +221,5 @@ Benjy Cui <benjytrys@gmail.com>
 Rodrigo Rosenfeld Rosas <rr.rosas@gmail.com>
 John Hoven <hovenj@gmail.com>
 Philip Jägenstedt <philip@foolip.org>
+Christian Kosmowski <ksmwsk@gmail.com>
 

src/css.js

@@ -340,7 +340,7 @@ jQuery.each([ "height", "width" ], function( i, name ) {
 			if ( computed ) {
 				// certain elements can have dimension info if we invisibly show them
 				// however, it must have a current display style that would benefit from this
-				return elem.offsetWidth === 0 && rdisplayswap.test( jQuery.css( elem, "display" ) ) ?
+				return rdisplayswap.test( jQuery.css( elem, "display" ) ) && elem.offsetWidth === 0 ?
 					jQuery.swap( elem, cssShow, function() {
 						return getWidthOrHeight( elem, name, extra );
 					}) :