Index: src/js/_enqueues/admin/postbox.js
===================================================================
--- src/js/_enqueues/admin/postbox.js	(revision 47225)
+++ src/js/_enqueues/admin/postbox.js	(working copy)
@@ -363,7 +363,7 @@
 			if ( side.length ) {
 				if ( side.children('.postbox:visible').length )
 					side.removeClass('empty-container');
-				else if ( $('#postbox-container-1').css('width') == '280px' )
+				else if ( $('.postbox-container-1').css('width') == '280px' )
 					side.addClass('empty-container');
 			}
 		},
Index: src/js/_enqueues/wp/editor/dfw.js
===================================================================
--- src/js/_enqueues/wp/editor/dfw.js	(revision 47225)
+++ src/js/_enqueues/wp/editor/dfw.js	(working copy)
@@ -31,7 +31,7 @@
 			$menuBar = $(),
 			$statusBar = $(),
 			$sideSortables = $( '#side-sortables' ),
-			$postboxContainer = $( '#postbox-container-1' ),
+			$postboxContainer = $( '.postbox-container-1' ),
 			$postBody = $('#post-body'),
 			fullscreen = window.wp.editor && window.wp.editor.fullscreen,
 			mceEditor,
Index: src/wp-admin/css/common.css
===================================================================
--- src/wp-admin/css/common.css	(revision 47225)
+++ src/wp-admin/css/common.css	(working copy)
@@ -2009,9 +2009,9 @@
 }
 
 .metabox-holder.columns-1 .postbox-container .empty-container,
-.columns-2 #postbox-container-3 .empty-container,
-.columns-2 #postbox-container-4 .empty-container,
-.columns-3 #postbox-container-4 .empty-container {
+.columns-2 .postbox-container-3 .empty-container,
+.columns-2 .postbox-container-4 .empty-container,
+.columns-3 .postbox-container-4 .empty-container {
 	border: 0 none;
 	height: 0;
 	min-height: 0;
@@ -2023,7 +2023,7 @@
 	float: left;
 }
 
-#post-body.columns-2 #postbox-container-1 {
+#post-body.columns-2 .postbox-container-1 {
 	float: right;
 	margin-right: -300px;
 	width: 280px;
Index: src/wp-admin/css/dashboard.css
===================================================================
--- src/wp-admin/css/dashboard.css	(revision 47225)
+++ src/wp-admin/css/dashboard.css	(working copy)
@@ -7,8 +7,8 @@
 }
 
 #wpbody-content #dashboard-widgets.columns-2 .postbox-container-2,
-#wpbody-content #dashboard-widgets.columns-2 #postbox-container-3,
-#wpbody-content #dashboard-widgets.columns-2 #postbox-container-4 {
+#wpbody-content #dashboard-widgets.columns-2 .postbox-container-3,
+#wpbody-content #dashboard-widgets.columns-2 .postbox-container-4 {
 	float: right;
 	width: 50.5%;
 }
@@ -17,12 +17,12 @@
 	width: 33.5%;
 }
 
-#wpbody-content #dashboard-widgets.columns-3 #postbox-container-1 {
+#wpbody-content #dashboard-widgets.columns-3 .postbox-container-1 {
 	width: 33%;
 }
 
-#wpbody-content #dashboard-widgets.columns-3 #postbox-container-3,
-#wpbody-content #dashboard-widgets.columns-3 #postbox-container-4 {
+#wpbody-content #dashboard-widgets.columns-3 .postbox-container-3,
+#wpbody-content #dashboard-widgets.columns-3 .postbox-container-4 {
 	float: right;
 }
 
@@ -34,7 +34,7 @@
 	width: 25%;
 }
 
-#dashboard-widgets-wrap .columns-3 #postbox-container-4 .empty-container {
+#dashboard-widgets-wrap .columns-3 .postbox-container-4 .empty-container {
 	border: none !important;
 }
 
@@ -43,14 +43,14 @@
 }
 
 .ie8 #wpbody-content #dashboard-widgets .postbox-container-2,
-.ie8 #wpbody-content #dashboard-widgets #postbox-container-3,
-.ie8 #wpbody-content #dashboard-widgets #postbox-container-4 {
+.ie8 #wpbody-content #dashboard-widgets .postbox-container-3,
+.ie8 #wpbody-content #dashboard-widgets .postbox-container-4 {
 	float: right;
 	width: 50.5%;
 }
 
-.ie8 #dashboard-widgets #postbox-container-3 .empty-container,
-.ie8 #dashboard-widgets #postbox-container-4 .empty-container {
+.ie8 #dashboard-widgets .postbox-container-3 .empty-container,
+.ie8 #dashboard-widgets .postbox-container-4 .empty-container {
 	border: 0 none;
 	height: 0;
 	min-height: 0;
@@ -1113,21 +1113,21 @@
 	}
 
 	#wpbody-content #dashboard-widgets .postbox-container-2,
-	#wpbody-content #dashboard-widgets #postbox-container-3,
-	#wpbody-content #dashboard-widgets #postbox-container-4 {
+	#wpbody-content #dashboard-widgets .postbox-container-3,
+	#wpbody-content #dashboard-widgets .postbox-container-4 {
 		float: right;
 		width: 50.5%;
 	}
 
-	#dashboard-widgets #postbox-container-3 .empty-container,
-	#dashboard-widgets #postbox-container-4 .empty-container {
+	#dashboard-widgets .postbox-container-3 .empty-container,
+	#dashboard-widgets .postbox-container-4 .empty-container {
 		border: 0 none;
 		height: 0;
 		min-height: 0;
 	}
 
-	#dashboard-widgets #postbox-container-3 .empty-container:after,
-	#dashboard-widgets #postbox-container-4 .empty-container:after {
+	#dashboard-widgets .postbox-container-3 .empty-container:after,
+	#dashboard-widgets .postbox-container-4 .empty-container:after {
 		display: none;
 	}
 
@@ -1163,22 +1163,22 @@
 		width: 33.5%;
 	}
 
-	#wpbody-content #dashboard-widgets #postbox-container-1 {
+	#wpbody-content #dashboard-widgets .postbox-container-1 {
 		width: 33%;
 	}
 
-	#wpbody-content #dashboard-widgets #postbox-container-3,
-	#wpbody-content #dashboard-widgets #postbox-container-4 {
+	#wpbody-content #dashboard-widgets .postbox-container-3,
+	#wpbody-content #dashboard-widgets .postbox-container-4 {
 		float: right;
 	}
 
-	#dashboard-widgets #postbox-container-4 .empty-container {
+	#dashboard-widgets .postbox-container-4 .empty-container {
 		border: 0 none;
 		height: 0;
 		min-height: 0;
 	}
 
-	#dashboard-widgets #postbox-container-4 .empty-container:after {
+	#dashboard-widgets .postbox-container-4 .empty-container:after {
 		display: none;
 	}
 
Index: src/wp-admin/css/edit.css
===================================================================
--- src/wp-admin/css/edit.css	(revision 47225)
+++ src/wp-admin/css/edit.css	(working copy)
@@ -1420,13 +1420,13 @@
 		margin: 0;
 	}
 
-	#wpbody-content #post-body.columns-2 #postbox-container-1 {
+	#wpbody-content #post-body.columns-2 .postbox-container-1 {
 		margin-right: 0;
 		width: 100%;
 	}
 
-	.poststuff #postbox-container-1 .empty-container,
-	.poststuff #postbox-container-1 #side-sortables:empty {
+	.poststuff .postbox-container-1 .empty-container,
+	.poststuff .postbox-container-1 #side-sortables:empty {
 		border: 0 none;
 		height: 0;
 		min-height: 0;
Index: src/wp-admin/css/ie.css
===================================================================
--- src/wp-admin/css/ie.css	(revision 47225)
+++ src/wp-admin/css/ie.css	(working copy)
@@ -14,14 +14,14 @@
 }
 
 #wpbody-content #dashboard-widgets .postbox-container-2,
-#wpbody-content #dashboard-widgets #postbox-container-3,
-#wpbody-content #dashboard-widgets #postbox-container-4 {
+#wpbody-content #dashboard-widgets .postbox-container-3,
+#wpbody-content #dashboard-widgets .postbox-container-4 {
 	float: right;
 	width: 50.5%;
 }
 
-#dashboard-widgets #postbox-container-3 .empty-container,
-#dashboard-widgets #postbox-container-4 .empty-container {
+#dashboard-widgets .postbox-container-3 .empty-container,
+#dashboard-widgets .postbox-container-4 .empty-container {
 	border: 0 none;
 	height: 0;
 	min-height: 0;
@@ -38,7 +38,7 @@
 	width: 97%;
 }
 
-#post-body.columns-2 #postbox-container-1 {
+#post-body.columns-2 .postbox-container-1 {
 	padding-left: 19px;
 }
 
Index: src/wp-admin/edit-form-advanced.php
===================================================================
--- src/wp-admin/edit-form-advanced.php	(revision 47225)
+++ src/wp-admin/edit-form-advanced.php	(working copy)
@@ -639,7 +639,7 @@
 ?>
 </div><!-- /post-body-content -->
 
-<div id="postbox-container-1" class="postbox-container">
+<div class="postbox-container-1 postbox-container">
 <?php
 
 if ( 'page' == $post_type ) {
Index: src/wp-admin/edit-form-comment.php
===================================================================
--- src/wp-admin/edit-form-comment.php	(revision 47225)
+++ src/wp-admin/edit-form-comment.php	(working copy)
@@ -85,7 +85,7 @@
 </div>
 </div><!-- /post-body-content -->
 
-<div id="postbox-container-1" class="postbox-container">
+<div class="postbox-container-1 postbox-container">
 <div id="submitdiv" class="stuffbox" >
 <h2><?php _e( 'Status' ); ?></h2>
 <div class="inside">
Index: src/wp-admin/edit-link-form.php
===================================================================
--- src/wp-admin/edit-link-form.php	(revision 47225)
+++ src/wp-admin/edit-link-form.php	(working copy)
@@ -135,7 +135,7 @@
 </div>
 </div><!-- /post-body-content -->
 
-<div id="postbox-container-1" class="postbox-container">
+<div class="postbox-container-1 postbox-container">
 <?php
 
 /** This action is documented in wp-admin/includes/meta-boxes.php */
Index: src/wp-admin/includes/dashboard.php
===================================================================
--- src/wp-admin/includes/dashboard.php	(revision 47225)
+++ src/wp-admin/includes/dashboard.php	(working copy)
@@ -242,16 +242,16 @@
 
 	?>
 <div id="dashboard-widgets" class="metabox-holder<?php echo $columns_css; ?>">
-	<div id="postbox-container-1" class="postbox-container">
+	<div class="postbox-container-1 postbox-container">
 	<?php do_meta_boxes( $screen->id, 'normal', '' ); ?>
 	</div>
 	<div class="postbox-container-2 postbox-container">
 	<?php do_meta_boxes( $screen->id, 'side', '' ); ?>
 	</div>
-	<div id="postbox-container-3" class="postbox-container">
+	<div class="postbox-container-3 postbox-container">
 	<?php do_meta_boxes( $screen->id, 'column3', '' ); ?>
 	</div>
-	<div id="postbox-container-4" class="postbox-container">
+	<div class="postbox-container-4 postbox-container">
 	<?php do_meta_boxes( $screen->id, 'column4', '' ); ?>
 	</div>
 </div>