Sort Order for Custom Module Builder

I created a custom module: Booklet. It has sub-content items called Pages. I created a Number field called SortOrder for the Pages. However, when I go into advanced mode to sort by SortOrder, it orders them as if the field were text, i.e. 1,10,11,13,2,20,21,3  instead of 1,2,3, 4, 5,6,7,8,9,19,11,etc.
Suggestions?

Actually, it looks like it might be a bug. Every time I try to change the sort items to "As in Advanced mode" , it changes the drop down back to Date Published or Title.

Steps to reproduce:

Using the module builder, create a module called "Booklet". Add subcontent items called "Pages" with a SortOrder field.

Create a booklet with three pages.

Add the Booklet widget to the page.  Edit the settings so that it shows one particular booklet (the one you created) Select "No limit and paging" Select Sort Items "As in advanced mode".

Click the advanced button and navigate to the templates.

Change the sorting based on "SortOrder ASC"

Click save. It will bring you back to the simple mode and expand paging and sorting. it will change the Sort Item back to Last published.

I recorded a video but it won't let me attach it to the forum.

Hello Amanda,

I was not able to reproduce the reported behavior on my end. I have used Sitefinity 6.0. Additionally I have recorded a short video, so please let me know if I am missing something.

@Amanda 

It's a bug I reported back in January: www.sitefinity.com/.../5-3-configuring-custom-module-wigets-not-working

@Pavel 
The clue here is:  sub-content items called Pages
Pits shows resolved but as per post above its not: www.telerik.com/.../pits.aspx

Hoping for 6.1 to have that fixed!

Markus

@Pavel
I think Mark nailed it on the head. I did also submit a support ticket with the video to show the error. It does appear to be a bug. I also hope it's fixed in 6.1

@Markus
Thanks! I'll keep an eye on the PITS ticket.