Hi rezagc,

You can ignore the code I sent before. I thought you talking about the bottom bar menu "preview".

If you want to change the size of the preview dialog, please try the way below.

1. Open file  \CuteSoft_Client\CuteEditor\Scripts\Constant.js

2. Find section below. You can change the widht and hieght directly. 

editorconstant._previewDialogFeature = "dialogWidth:640px;dialogHeight:480px;resizable:1"; 

Regards,

Ken