check if json apply needs a not yet instanciated app.js object and instanciate it in that case

phpgwapi/js/egw_json.js

@@ -485,6 +485,12 @@ egw_json_request.prototype.handleResponse = function(data, textStatus, XMLHttpRe
 						{
 
 							var parts = res.data.func.split(".");
+							// check if we need a not yet instanciated app.js object --> instanciate it now
+							if (parts.length == 3 && typeof window.app[parts[1]] == 'undefined' &&
+								typeof window.app.classes[parts[1]] == 'function')
+							{
+								window.app[parts[1]] = new window.app.classes[parts[1]]();
+							}
 							if(parts.length == 3 && typeof window.app[parts[1]] == "object" &&
 								typeof window.app[parts[1]][parts[2]] == "function")
 							{

phpgwapi/js/jsapi/egw_json.js

@@ -332,10 +332,18 @@ egw.extend('json', egw.MODULE_WND_LOCAL, function(_app, _wnd) {
 			var parts = res.data.func.split('.');
 			var func = parts.pop();
 			var parent = req.egw.window;
-			for(var i=0; i < parts.length && typeof parent[parts[i]] != 'undefined'; ++i)
+			for(var i=0; i < parts.length; ++i)
+			{
+				if (typeof parent[parts[i]] != 'undefined')
 				{
 					parent = parent[parts[i]];
 				}
+				// check if we need a not yet instanciated app.js object --> instanciate it now
+				else if (i == 1 && parts[0] == 'app' && typeof req.egw.window.app.classes[parts[1]] == 'function')
+				{
+					parent = parent[parts[1]] = new req.egw.window.app.classes[parts[1]]();
+				}
+			}
 			if (typeof parent[func] == 'function')
 			{
 				try