ftr/PartsInGoToMenu: fix wrong handling if there are no parts in source

due changes in last commit (10ba464) the array also exist if there are no parts, therefore its necessary to check for its lenght and not existence

app/view/window/source/SourceView.js

@@ -255,7 +255,7 @@ Ext.define('EdiromOnline.view.window.source.SourceView', {
 
         // iterate over submitted movements and push them to movementItems variable
         movements.data.each(function(movement) {
-            if(movement.data.parts === null) {
+            if(movement.data.parts.length === 0) {
                 movementItems.push({
                     text: movement.get('name'),
                     handler: Ext.bind(me.gotoMovement, me, movement.get('id'), true)
@@ -308,7 +308,6 @@ Ext.define('EdiromOnline.view.window.source.SourceView', {
             });
         }
 
-
         // check if contains more than one item and save to variable as boolean
         var isDisabled = ((movementItems.length < 1) ? true : false);