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diff --git a/tests/unit/position/position.html b/tests/unit/position/position.html
index f3b1ad86ca8..041f47b99c3 100644
--- a/tests/unit/position/position.html
+++ b/tests/unit/position/position.html
@@ -47,6 +47,8 @@
 	<div id="bug-5280" style="height: 30px; width: 201px;">
 		<div style="width: 50px; height: 10px;"></div>
 	</div>
+
+	<iframe id="bug-9534" style="position: absolute; top: 0; left: 0; width: 20px; height: 20px;" s r></iframe>
 </div>
 
 </body>
diff --git a/tests/unit/position/position_core.js b/tests/unit/position/position_core.js
index e03d4c11152..b8a2e7eeae6 100644
--- a/tests/unit/position/position_core.js
+++ b/tests/unit/position/position_core.js
@@ -719,4 +719,24 @@ test( "bug #5280: consistent results (avoid fractional values)", function() {
 	deepEqual( offset1, offset2 );
 });
 
+test("bug #9534: position in iframe window", function() {
+	expect(1);
+
+	var iframe = $("#bug-9534")[0];
+
+	$(iframe.contentDocument.body).css({
+		"width" : "30px",
+		"height" : "30px"
+	});
+
+	collisionTest({
+		my : "center",
+		at : "center",
+		of : iframe.contentWindow
+	}, {
+		top : 5,
+		left : 5
+	}, "positioned to iframe window");
+});
+
 }( jQuery ) );
diff --git a/ui/jquery.ui.position.js b/ui/jquery.ui.position.js
index 21c3cef1b19..56aa642b4af 100644
--- a/ui/jquery.ui.position.js
+++ b/ui/jquery.ui.position.js
@@ -45,8 +45,8 @@ function getDimensions( elem ) {
 	}
 	if ( $.isWindow( raw ) ) {
 		return {
-			width: elem.width(),
-			height: elem.height(),
+			width: (typeof raw.innerWidth === "number") ? raw.innerWidth : elem.width(),
+			height: (typeof raw.innerHeight === "number") ? raw.innerHeight : elem.height(),
 			offset: { top: elem.scrollTop(), left: elem.scrollLeft() }
 		};
 	}
