Web AppBuilder Developer Edition - Can't create new Apps

[KieranO_Donnell2]

Hi all,

I've been using Web AppBuilder Developer Edition (1.2) since its release and have just run into a new error

I am unable to create any new Apps, as a blank box (like an error message would) appears with only the option to click Ok.
See screenshot below.

I have made a number of new apps with this latest Developer Edition of Web AppBuilder, and am still able to edit the existing apps.
This issue has only recently sprung up, and is seemingly random as nothing should have changed to create the problem.

Has anyone else experienced this problem?

Cheers,
Kieran

[RobertScheitlin__GISP]

Junshan,

  This is great... I work for creating a new app as well and trying to duplicate an app.