Add attachment display settings to the media modal.

* Add a media view for button groups.
* Add button dropdown containers.
* Add a dropdown property to the button media model.

fixes #22206, #21814, see #21390, #21813, #21598.


git-svn-id: https://develop.svn.wordpress.org/trunk@22247 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/css/buttons.css

@@ -229,6 +229,7 @@ TABLE OF CONTENTS:
 ---------------------------------------------------------------------------- */
 
 .button-group {
+	position: relative;
 	display: inline-block;
 	white-space: nowrap;
 	font-size: 0;
@@ -236,7 +237,6 @@ TABLE OF CONTENTS:
 }
 
 .button-group > .button {
-	position: relative;
 	display: inline-block;
 	border-radius: 0;
 	margin-right: -1px;
@@ -269,8 +269,34 @@ TABLE OF CONTENTS:
 	content: '\25BE';
 	display: inline-block;
 	font-size: 16px;
-	opacity: 0.8;
+	opacity: 0.9;
 	margin: 0 -0.25em;
 	text-align: center;
 	vertical-align: middle;
 }
+
+.button .dropdown {
+	display: none;
+	position: absolute;
+	top: 100%;
+	left: 0;
+	margin-top: 5px;
+	padding: 0.8em 1em;
+	border-radius: 3px;
+
+	background: #f5f5f5;
+	color: #333;
+	text-shadow: none;
+	box-shadow:
+		0 0 0 1px rgba( 0, 0, 0, 0.3 ),
+		1px 1px 2px rgba( 0, 0, 0, 0.1 );
+}
+
+.button.active .dropdown {
+	display: block;
+}
+
+.dropdown-flip-x .dropdown {
+	left: auto;
+	right: 0;
+}