Index: wp-admin/js/editor.js
===================================================================
--- wp-admin/js/editor.js	(revision 23314)
+++ wp-admin/js/editor.js	(working copy)
@@ -138,7 +138,7 @@
 
 	_wp_Autop : function(pee) {
 		var preserve_linebreaks = false, preserve_br = false,
-			blocklist = 'table|thead|tfoot|caption|col|colgroup|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|select|option|form|map|area|blockquote|address|math|style|p|h[1-6]|hr|fieldset|noscript|samp|legend|section|article|aside|hgroup|header|footer|nav|figure|figcaption|details|menu|summary';
+			blocklist = 'table|thead|tfoot|caption|col|colgroup|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|select|option|form|map|area|blockquote|address|math|style|p|h[1-6]|hr|fieldset|noscript|legend|section|article|aside|hgroup|header|footer|nav|figure|figcaption|details|menu|summary';
 
 		if ( pee.indexOf('<object') != -1 ) {
 			pee = pee.replace(/<object[\s\S]+?<\/object>/g, function(a){
Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 23314)
+++ wp-includes/formatting.php	(working copy)
@@ -220,7 +220,7 @@
 
 	$pee = preg_replace('|<br />\s*<br />|', "\n\n", $pee);
 	// Space things out a little
-	$allblocks = '(?:table|thead|tfoot|caption|col|colgroup|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|select|option|form|map|area|blockquote|address|math|style|p|h[1-6]|hr|fieldset|noscript|samp|legend|section|article|aside|hgroup|header|footer|nav|figure|figcaption|details|menu|summary)';
+	$allblocks = '(?:table|thead|tfoot|caption|col|colgroup|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|select|option|form|map|area|blockquote|address|math|style|p|h[1-6]|hr|fieldset|noscript|legend|section|article|aside|hgroup|header|footer|nav|figure|figcaption|details|menu|summary)';
 	$pee = preg_replace('!(<' . $allblocks . '[^>]*>)!', "\n$1", $pee);
 	$pee = preg_replace('!(</' . $allblocks . '>)!', "$1\n\n", $pee);
 	$pee = str_replace(array("\r\n", "\r"), "\n", $pee); // cross-platform newlines
Index: wp-includes/js/tinymce/wp-tinymce-schema.js
===================================================================
--- wp-includes/js/tinymce/wp-tinymce-schema.js	(revision 23314)
+++ wp-includes/js/tinymce/wp-tinymce-schema.js	(working copy)
@@ -441,7 +441,7 @@
 		textBlockElementsMap = createLookupTable('text_block_elements', 'h1 h2 h3 h4 h5 h6 p div address pre form ' +
 						'blockquote center dir fieldset header footer article section hgroup aside nav figure');
 		blockElementsMap = createLookupTable('block_elements', 'hr table tbody thead tfoot ' +
-						'th tr td li ol ul caption dl dt dd noscript menu isindex samp option datalist select optgroup', textBlockElementsMap);
+						'th tr td li ol ul caption dl dt dd noscript menu isindex option datalist select optgroup', textBlockElementsMap);
 
 		// Converts a wildcard expression string to a regexp for example *a will become /.*a/.
 		function patternToRegExp(str) {