Index: src/wp-includes/js/tinymce/tinymce.js
===================================================================
--- src/wp-includes/js/tinymce/tinymce.js	(revision 38442)
+++ src/wp-includes/js/tinymce/tinymce.js	(working copy)
@@ -36261,25 +36261,52 @@
 			return null;
 		}
 
+		function isTextBlock(node) {
+ 			var textBlocks = editor.schema.getTextBlockElements();
+ 			return node.nodeName in textBlocks;
+ 		}
+ 
+ 		function isEmpty(elm) {
+ 			return editor.dom.isEmpty(elm);
+ 		}
+
 		function mergeTextBlocks(direction, fromCaretPosition, toCaretPosition) {
-			var dom = editor.dom, fromBlock, toBlock, node, textBlocks;
+			var dom = editor.dom, fromBlock, toBlock, node, ceTarget;
+ 
+ 			fromBlock = dom.getParent(fromCaretPosition.getNode(), dom.isBlock);
+ 			toBlock = dom.getParent(toCaretPosition.getNode(), dom.isBlock);
 
 			if (direction === -1) {
-				if (isAfterContentEditableFalse(toCaretPosition) && isBlock(toCaretPosition.getNode(true))) {
+				ceTarget = toCaretPosition.getNode(true);
+ 				if (isAfterContentEditableFalse(toCaretPosition) && isBlock(ceTarget)) {
+ 					if (isTextBlock(fromBlock)) {
+ 						if (isEmpty(fromBlock)) {
+ 							dom.remove(fromBlock);
+ 						}
+ 
+ 						return CaretPosition.after(ceTarget).toRange();
+ 					}
+ 				
 					return deleteContentEditableNode(toCaretPosition.getNode(true));
 				}
 			} else {
-				if (isBeforeContentEditableFalse(fromCaretPosition) && isBlock(fromCaretPosition.getNode())) {
+				ceTarget = fromCaretPosition.getNode();
+ 				if (isBeforeContentEditableFalse(fromCaretPosition) && isBlock(ceTarget)) {
+ 					if (isTextBlock(toBlock)) {
+ 						if (isEmpty(toBlock)) {
+ 							dom.remove(toBlock);
+ 						}
+ 
+ 						return CaretPosition.before(ceTarget).toRange();
+ 					}
+ 
 					return deleteContentEditableNode(fromCaretPosition.getNode());
 				}
 			}
 
-			textBlocks = editor.schema.getTextBlockElements();
-			fromBlock = dom.getParent(fromCaretPosition.getNode(), dom.isBlock);
-			toBlock = dom.getParent(toCaretPosition.getNode(), dom.isBlock);
 
 			// Verify that both blocks are text blocks
-			if (fromBlock === toBlock || !textBlocks[fromBlock.nodeName] || !textBlocks[toBlock.nodeName]) {
+			if (fromBlock === toBlock || !isTextBlock(fromBlock) || !isTextBlock(toBlock)) {
 				return null;
 			}