Uncaught Client Side Exception

When running in debug mode (?debug) I see a big red exception report on top of my application.
I don’t get that exception when running without ?debug.
Should I assume this is a bug related to using the debug window?

See attached image.

Thanks
13114.png

It looks like from the error message that you are getting a NullPointerException from the client side code. It might be the debug window or it might be something else.

Are you using any addons or have you added some custom widgets to your project which might be causing it?