ScriptUI Blank Panel Error

So I have this script I'm writing:

var w=new Window ('palette');

var panelGroup=w.add("Panel",undefined,"Name");

panelGroup.alignChildren="left";

var scaleCheck=panelGroup.add("checkbox",undefined,"Scale");

var rotateCheck=panelGroup.add("checkbox",undefined,"Rotation");

var opacityCheck=panelGroup.add("checkbox",undefined,"Opacity");

var colorCheck=panelGroup.add("checkbox",undefined,"Color");

var customCheck=panelGroup.add("checkbox",undefined,"Custom");

var applyButton=w.add("button",undefined,"Apply");

w.layout.layout(false);

w.center();

w.show();

I'm new to scripting, but basically I'm trying to create a simple UI with checkboxes with different properties applied. Whenever I run it through ESTK it looks perfect. But when I run through the ScriptUI Panels folder from the "window" tab in AE it does this:

Essentially creating a huge dockable blank panel, and my smaller panel that is still undockable. Any help is appreciated!