Index: src/wp-includes/css/media-views.css
===================================================================
--- src/wp-includes/css/media-views.css	(revision 31323)
+++ src/wp-includes/css/media-views.css	(working copy)
@@ -235,22 +235,11 @@
 }
 
 .media-toolbar-secondary {
-	position: relative;
 	float: left;
-	-webkit-box-sizing: border-box;
-	-moz-box-sizing: border-box;
-	box-sizing: border-box;
-	padding-right: 20px;
 	height: 100%;
 	max-width: 66%;
 }
 
-.media-toolbar-secondary .spinner {
-	position: absolute;
-	top: 2px;
-	right: 0px;
-}
-
 .media-toolbar-primary > .media-button,
 .media-toolbar-primary > .media-button-group {
 	margin-left: 10px;
@@ -751,7 +740,6 @@
 	margin-top: 11px;
 	margin-right: 2%;
 	max-width: 47%;
-	width: 100%; /* prevents options from invisibly taking up horizontal space */
 }
 
 /**
@@ -1508,7 +1496,8 @@
 	background: url(../images/spinner.gif) no-repeat;
 	-webkit-background-size: 20px 20px;
 	background-size: 20px 20px;
-	display: none;
+	display: inline-block;
+	visibility: hidden;
 	opacity: 0.7;
 	filter: alpha(opacity=70);
 	width: 20px;
@@ -2371,7 +2360,7 @@
 	}
 
 	.media-modal .attachments-browser .media-toolbar .spinner {
-		margin: 14px 0 0;
+		margin: 14px 8px 0;
 	}
 
 	/* Text inputs need to be 16px, or they force zooming on iOS */
Index: src/wp-includes/js/media-views.js
===================================================================
--- src/wp-includes/js/media-views.js	(revision 31323)
+++ src/wp-includes/js/media-views.js	(working copy)
@@ -7792,7 +7792,7 @@
 		show: function() {
 			if ( ! this.spinnerTimeout ) {
 				this.spinnerTimeout = _.delay(function( $el ) {
-					$el.show();
+					$el.css('visibility', 'visible');
 				}, this.delay, this.$el );
 			}
 
@@ -7800,7 +7800,7 @@
 		},
 
 		hide: function() {
-			this.$el.hide();
+			this.$el.css('visibility', 'hidden');
 			this.spinnerTimeout = clearTimeout( this.spinnerTimeout );
 
 			return this;