Index: lams_central/web/css/newLesson.css
===================================================================
diff -u -r4ab52d60ee545b9b76bcc65f75c5a400f6105c30 -r16d6f695b233ecc989e47a607820ab78f07e7caf
--- lams_central/web/css/newLesson.css	(.../newLesson.css)	(revision 4ab52d60ee545b9b76bcc65f75c5a400f6105c30)
+++ lams_central/web/css/newLesson.css	(.../newLesson.css)	(revision 16d6f695b233ecc989e47a607820ab78f07e7caf)
@@ -69,6 +69,11 @@
 	border-right: thin dotted #2E6E9E;
 }
 
+div#learningDesignTree {
+	overflow: auto;
+	height: 385px;
+}
+
 .ygtv-highlight1, .ygtv-highlight1 .ygtvlabel {
 	background-color: #dfeffc;
 }
@@ -96,6 +101,10 @@
 	display: none;
 }
 
+img#ldScreenshotLoading, div#ldNotChosenError  {
+	padding-top: 140px;
+}
+
 td#lessonNameCell {
 	height: 20px;
 	padding: 0px 0px 5px 10px;
Index: lams_central/web/includes/javascript/newLesson.js
===================================================================
diff -u -r4ab52d60ee545b9b76bcc65f75c5a400f6105c30 -r16d6f695b233ecc989e47a607820ab78f07e7caf
--- lams_central/web/includes/javascript/newLesson.js	(.../newLesson.js)	(revision 4ab52d60ee545b9b76bcc65f75c5a400f6105c30)
+++ lams_central/web/includes/javascript/newLesson.js	(.../newLesson.js)	(revision 16d6f695b233ecc989e47a607820ab78f07e7caf)
@@ -1,5 +1,8 @@
 // ********** MAIN FUNCTIONS **********
-
+var tree;
+var lastSelectedUsers = [];
+var submitInProgress = false;
+		
 function initLessonTab(){
 	$('#ldScreenshotAuthor').load(function(){
 		// hide "loading" animation
@@ -16,7 +19,7 @@
 	var treeNodes = parseFolderTreeNode(folderContents);
 	// there should be no focus, just highlight
 	YAHOO.widget.TreeView.FOCUS_CLASS_NAME = null;
-	tree = new YAHOO.widget.TreeView('learningDesignTreeCell', treeNodes);
+	tree = new YAHOO.widget.TreeView('learningDesignTree', treeNodes);
 	tree.singleNodeHighlight = true;
 	tree.subscribe('clickEvent', function(event){
 		if (!event.node.data.learningDesignId){
@@ -32,6 +35,8 @@
 			$('#ldScreenshotLoading').css('display', 'inline');
 			$('#ldScreenshotAuthor').attr('src', LD_THUMBNAIL_URL_BASE + event.node.data.learningDesignId);
 			$('#ldScreenshotAuthor').css('width', 'auto').css('height', 'auto');
+		} else {
+			toggleCanvasResize(CANVAS_RESIZE_OPTION_NONE);
 		}
 	});
 	tree.subscribe('clickEvent',tree.onEventToggleHighlight);
@@ -179,24 +184,29 @@
 	});
 	
 	$('#schedulingEnableField').change(function(){
-		$('#schedulingDatetimeField').prop('disabled', !$(this).is(':checked'));
+		$('#schedulingDatetimeField').val(null).prop('disabled', !$(this).is(':checked'));
 	});
 	
 	$('#startMonitorField').change(function(){
 		var checked = !$(this).is(':checked');
 		var schedulingEnableField = $('#schedulingEnableField');
 		if (!checked) {
 			schedulingEnableField.attr('checked', false);
-			$('#schedulingDatetimeField').prop('disabled', true);
+			$('#schedulingDatetimeField').val(null).prop('disabled', true);
 		}
 		schedulingEnableField.prop('disabled', !checked);
 	});
 	
-	$('#schedulingDatetimeField').datetimepicker();
+	$('#schedulingDatetimeField').datetimepicker({
+		'minDate' : 0
+	});
 }
 
 
 function addLesson(){
+	if (submitInProgress) {
+		return;
+	}
 	// some validation at first
 	var lessonName = $('#lessonNameInput').val();
 	if (lessonName){
@@ -246,6 +256,7 @@
 		$('#splitNumberLessonsField').val(instances);
 	}
 	
+	submitInProgress = true;
 	$('#lessonForm').ajaxSubmit({
 		'success' : function(){
 			window.parent.closeAddLessonDialog(true);
Index: lams_central/web/newLesson.jsp
===================================================================
diff -u -r4ab52d60ee545b9b76bcc65f75c5a400f6105c30 -r16d6f695b233ecc989e47a607820ab78f07e7caf
--- lams_central/web/newLesson.jsp	(.../newLesson.jsp)	(revision 4ab52d60ee545b9b76bcc65f75c5a400f6105c30)
+++ lams_central/web/newLesson.jsp	(.../newLesson.jsp)	(revision 16d6f695b233ecc989e47a607820ab78f07e7caf)
@@ -22,8 +22,6 @@
 	<script type="text/javascript" src="includes/javascript/yui/treeview-min.js" ></script>
 	<script type="text/javascript" src="includes/javascript/newLesson.js"></script>
 	<script type="text/javascript">
-		var tree;
-		var lastSelectedUsers = [];
 		var userId = '<lams:user property="userID"/>';
 		var folderContents = ${folderContents};
 		var users = ${users};
@@ -74,6 +72,7 @@
 		<table class="tabTable">
 			<tr>
 				<td id="learningDesignTreeCell" rowspan="3">
+					<div id="learningDesignTree"></div>
 				</td>
 				<td id="canvasControlCell">
 					<a id="toggleCanvasResizeLink" href="#"></a>
@@ -168,8 +167,6 @@
 			<input id="schedulingDatetimeField" name="schedulingDatetime" disabled="disabled" />
 		</form>
 	</div>
-	
-	
 </div>
 </body>
 </lams:html>
\ No newline at end of file