It seems that composer is using Microsoft's Ajax which is causing the problem. I can't see anything wrong with the way we've setup the page as it is exactly the same as the other composer pages?
Error: a is null Source File: http://test/ScriptResource.axd?d=ie9cioxQAV9f80NptsWUWonAatMCfEEcJtD-OTunbMe_gI0XNYMRlyrm2huc5fxMciArspHNVZCgjqKG6mj8yi6BAJP7i0RaGTwgnD9lHy0LfY1lcjKjPVYc6sheMO-If2ZZkIJ-hH-Og1s2z1-k0EFJ_IBpbDCGgLFBrg6chmw1&t=2610f696Line: 5Error: oConfirmDlg_oDialog is not definedSource File: http://test/Dropit/Plugin/Extension/UI/Js/x3.min.jsLine: 1
Its been a while since we last spoke :-P
We actually came across a similar problem. In our case we were including a jQuery library which was conflicting with the composer one.
Found a post here that helped me narrow down the problem. Also have a look here if you are using the jQuery library.
So if you are including jQuery somewhere in your project, you will need to do the following
Then just be sure to use "j" instead of "$" throughout the project.
Hope this helps
You can also without having to set: