Index: lams_central/src/java/org/lamsfoundation/lams/web/HomeAction.java
===================================================================
diff -u -r3dbf966d900adefc34cdad501d3c392118451cd9 -r27a58f395dec9927221147dac08a0b75213fd354
--- lams_central/src/java/org/lamsfoundation/lams/web/HomeAction.java	(.../HomeAction.java)	(revision 3dbf966d900adefc34cdad501d3c392118451cd9)
+++ lams_central/src/java/org/lamsfoundation/lams/web/HomeAction.java	(.../HomeAction.java)	(revision 27a58f395dec9927221147dac08a0b75213fd354)
@@ -23,6 +23,7 @@
 /* $$Id$$ */
 package org.lamsfoundation.lams.web;
 
+import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.OutputStream;
@@ -61,7 +62,6 @@
 import org.lamsfoundation.lams.usermanagement.Organisation;
 import org.lamsfoundation.lams.usermanagement.Role;
 import org.lamsfoundation.lams.usermanagement.User;
-import org.lamsfoundation.lams.usermanagement.dto.UserBasicDTO;
 import org.lamsfoundation.lams.usermanagement.dto.UserDTO;
 import org.lamsfoundation.lams.usermanagement.exception.UserAccessDeniedException;
 import org.lamsfoundation.lams.usermanagement.service.IUserManagementService;
@@ -268,7 +268,7 @@
     @SuppressWarnings("unchecked")
     public ActionForward addLesson(ActionMapping mapping, ActionForm form, HttpServletRequest req,
 	    HttpServletResponse res)
-		    throws IOException, UserAccessDeniedException, JSONException, RepositoryCheckedException {
+	    throws IOException, UserAccessDeniedException, JSONException, RepositoryCheckedException {
 	UserDTO userDTO = getUser();
 	Integer organisationID = new Integer(WebUtil.readIntParam(req, "organisationID"));
 
@@ -336,7 +336,7 @@
      */
     public ActionForward getFolderContents(ActionMapping mapping, ActionForm form, HttpServletRequest req,
 	    HttpServletResponse res)
-		    throws UserAccessDeniedException, JSONException, IOException, RepositoryCheckedException {
+	    throws UserAccessDeniedException, JSONException, IOException, RepositoryCheckedException {
 	Integer folderID = WebUtil.readIntParam(req, "folderID", true);
 	boolean allowInvalidDesigns = WebUtil.readBooleanParam(req, "allowInvalidDesigns", false);
 	String folderContentsJSON = getWorkspaceManagementService().getFolderContentsJSON(folderID,
@@ -350,6 +350,13 @@
     public ActionForward getLearningDesignThumbnail(ActionMapping mapping, ActionForm form, HttpServletRequest req,
 	    HttpServletResponse res) throws JDOMException, IOException {
 	Long learningDesignId = WebUtil.readLongParam(req, CentralConstants.PARAM_LEARNING_DESIGN_ID);
+	String imagePath = LearningDesignService.getLearningDesignSVGPath(learningDesignId);
+	File imageFile = new File(imagePath);
+	if (!imageFile.canRead()) {
+	    res.sendError(HttpServletResponse.SC_NOT_FOUND);
+	    return null;
+	}
+
 	boolean download = WebUtil.readBooleanParam(req, "download", false);
 	// should the image be downloaded or a part of page?
 	if (download) {
@@ -363,7 +370,6 @@
 	    res.setContentType("image/svg+xml");
 	}
 
-	String imagePath = LearningDesignService.getLearningDesignSVGPath(learningDesignId);
 	FileInputStream input = new FileInputStream(imagePath);
 	OutputStream output = res.getOutputStream();
 	IOUtils.copy(input, output);
Index: lams_central/web/includes/javascript/addLesson.js
===================================================================
diff -u -r9bb68cb1df5f57c18e966963fd308e9a82743671 -r27a58f395dec9927221147dac08a0b75213fd354
--- lams_central/web/includes/javascript/addLesson.js	(.../addLesson.js)	(revision 9bb68cb1df5f57c18e966963fd308e9a82743671)
+++ lams_central/web/includes/javascript/addLesson.js	(.../addLesson.js)	(revision 27a58f395dec9927221147dac08a0b75213fd354)
@@ -17,6 +17,23 @@
 		var resized = resizeImage('ldScreenshotAuthor', 477);
 		toggleCanvasResize(resized ? CANVAS_RESIZE_OPTION_FIT
 				: CANVAS_RESIZE_OPTION_NONE);
+	}).error(function(){
+		// the LD SVG is missing, try to re-generate it
+		var image = $(this),
+			learningDesignID = $(this).data('learningDesignID');
+		
+		// iframe just to load Authoring for a single purpose, generate the SVG
+		$('<iframe />').appendTo('body').load(function(){
+			// call svgGenerator.jsp code to store LD SVG on the server
+			var frame = $(this),
+				win = frame[0].contentWindow || frame[0].contentDocument;
+			win.GeneralLib.saveLearningDesignImage();
+			frame.remove();
+			// load the image again, avoid caching
+			image.attr('src', LD_THUMBNAIL_URL_BASE + learningDesignID + '&_t=' + new Date().getTime());
+		}).attr('src', LAMS_URL 
+					   + 'authoring/author.do?method=generateSVG&selectable=false&learningDesignID='
+					   + learningDesignID);
 	});
 	
 	// generate LD initial tree; folderContents is declared in newLesson.jsp
@@ -61,8 +78,11 @@
 		$('.ldChoiceDependentCanvasElement').css('display', 'none');
 		if (event.node.highlightState == 0) {
 			$('#ldScreenshotLoading').css('display', 'inline');
-			$('#ldScreenshotAuthor').attr('src', LD_THUMBNAIL_URL_BASE + event.node.data.learningDesignId);
-			$('#ldScreenshotAuthor').css('width', 'auto').css('height', 'auto');
+			$('#ldScreenshotAuthor').data('learningDesignID', event.node.data.learningDesignId)
+									.attr('src', LD_THUMBNAIL_URL_BASE + event.node.data.learningDesignId 
+																	   + '&_t=' + new Date().getTime())
+									.css('width', 'auto')
+									.css('height', 'auto');
 		} else {
 			toggleCanvasResize(CANVAS_RESIZE_OPTION_NONE);
 		}
Index: lams_central/web/includes/javascript/authoring/authoringGeneral.js
===================================================================
diff -u -r3dbf966d900adefc34cdad501d3c392118451cd9 -r27a58f395dec9927221147dac08a0b75213fd354
--- lams_central/web/includes/javascript/authoring/authoringGeneral.js	(.../authoringGeneral.js)	(revision 3dbf966d900adefc34cdad501d3c392118451cd9)
+++ lams_central/web/includes/javascript/authoring/authoringGeneral.js	(.../authoringGeneral.js)	(revision 27a58f395dec9927221147dac08a0b75213fd354)
@@ -2057,8 +2057,8 @@
 		
 		// -20 so Chrome does not create unnecessary scrollbars when dropping a tool template to canvas
 		// +50 so there is space for rubbish bin
-		width = Math.max(0, width, canvas.width()) - 20;
-		height = Math.max(0, height + (isReadOnlyMode ? 20 : 50), canvas.height()) - 20;
+		width = Math.max(0, width, canvas.width() - 20);
+		height = Math.max(0, height + (isReadOnlyMode ? 20 : 50), canvas.height() - 20);
 		
 		paper.attr({
 			'width'  : width, 
Index: lams_monitoring/web/includes/javascript/monitorLesson.js
===================================================================
diff -u -r3dbf966d900adefc34cdad501d3c392118451cd9 -r27a58f395dec9927221147dac08a0b75213fd354
--- lams_monitoring/web/includes/javascript/monitorLesson.js	(.../monitorLesson.js)	(revision 3dbf966d900adefc34cdad501d3c392118451cd9)
+++ lams_monitoring/web/includes/javascript/monitorLesson.js	(.../monitorLesson.js)	(revision 27a58f395dec9927221147dac08a0b75213fd354)
@@ -6,7 +6,7 @@
 	flaFormat = false,
 // DIV container for lesson/branching SVG
 // it gets accessed so many times it's worth to cache it here
-	sequenceCanvas = null,
+	sequenceCanvas = $('#sequenceCanvas'),
 // info box show timeout
 	sequenceInfoTimeout = 10000,
 // which learner was selected in the search box
@@ -762,30 +762,8 @@
 		// put bottom layer, LD SVG
 		sequenceCanvas.html(originalSequenceCanvas);
 	} else {
-		// fetch SVG just once, since it is immutable
-		$.ajax({
-			dataType : 'text',
-			url : LAMS_URL + 'home.do',
-			async : false,
-			cache : false,
-			data : {
-				'method'    : 'getLearningDesignThumbnail',
-				'ldId'      : ldId
-			},
-			success : function(response) {
-				sequenceCanvasFirstFetch = true;
-				originalSequenceCanvas = response;
-				// store body dimensions before manipulating HTML
-				// otherwise resizing will yield bad results
-				var width = $('body').width(),
-					height = $('body').height();
-				sequenceCanvas = $('#sequenceCanvas')
-					// remove previously set padding and dimensions, if any
-					.removeAttr('style')
-					.html(originalSequenceCanvas);
-				resizeSequenceCanvas(width, height);
-			}
-		});
+		sequenceCanvasFirstFetch = true;
+		loadLearningDesignSVG();
 	}
 	
 	// clear all completed learner icons except the door
@@ -890,7 +868,50 @@
 	});
 }
 
+function loadLearningDesignSVG() {
+	// fetch SVG just once, since it is immutable
+	$.ajax({
+		dataType : 'text',
+		url : LAMS_URL + 'home.do',
+		async : false,
+		cache : false,
+		data : {
+			'method'    : 'getLearningDesignThumbnail',
+			'ldId'      : ldId
+		},
+		success : function(response) {
+			originalSequenceCanvas = response;
+			// store body dimensions before manipulating HTML
+			// otherwise resizing will yield bad results
+			var width = $('body').width(),
+				height = $('body').height();
+			// Remove previously set padding and dimensions, if any.
+			// For some reason sequenceCanvas needs to be assigned again here.
+			sequenceCanvas = $('#sequenceCanvas').removeAttr('style')
+						  						 .html(originalSequenceCanvas);
+			resizeSequenceCanvas(width, height);
+		},
+		error : function(error) {
+			// the LD SVG is missing, try to re-generate it; if it is an another error, fail
+			if (error.status != 404) {
+				return;
+			}
+			// iframe just to load Authoring for a single purpose, generate the SVG
+			$('<iframe />').appendTo('body').load(function(){
+				// call svgGenerator.jsp code to store LD SVG on the server
+				var frame = $(this),
+					win = frame[0].contentWindow || frame[0].contentDocument;
+				win.GeneralLib.saveLearningDesignImage();
+				frame.remove();
+				// load the image again
+				loadLearningDesignSVG();
+			}).attr('src', LAMS_URL 
+						   + 'authoring/author.do?method=generateSVG&selectable=false&learningDesignID=' + ldId);
+		}
+	});
+}
 
+
 /**
  * Forces given learner to move to activity indicated on SVG by coordinated (drag-drop)
  */
@@ -1363,9 +1384,9 @@
 	$('#sequenceSearchedLearnerHighlighter').hide();
 	sequenceSearchedLearner = null;
 	if (refresh) {
-	updateSequenceTab();
+		updateSequenceTab();
+	}
 }
-}
 
 
 /**
@@ -1528,9 +1549,8 @@
  * Adjusts sequence canvas (SVG) based on space available in the dialog.
  */
 function resizeSequenceCanvas(width, height){
-	var sequenceCanvas = $('#sequenceCanvas'),
-		// can it be done nicer?
-		canvasHeight = height - $('#tabs>ul').height() - $('#sequenceTopButtonsContainer').height()
+	// can the calculation it be done nicer?
+	var canvasHeight = height - $('#tabs>ul').height() - $('#sequenceTopButtonsContainer').height()
 	  				   - Math.min(20, $('#completedLearnersContainer').height()) - 45,
 		canvasWidth = width - 15,
 		svg = $('svg', sequenceCanvas),