Multi Page app displays blank page when a third page is created

Dash Python
1

Hi Everyone,

I have a multipage app with an index and another page that works fine.
Now I’m adding a new page and the browser only shows a BLANK page both for the index and the other two pages.
Seems like the layout is not loaded at all. And the server does not give any error message.

I’ve seen that this behaviour may arise when you have new compoonent libraries layout elements that are created by a callback (Display tables in Dash - #40 by chriddyp). In this case I’m not using anything different in the new page. Actually I tried just putting some html elements in the layout of the new page and the result is the same.

It’s a bit complicated to share the code here since the dash app is embedded in a larger Flask app.
I wanted to know if this is a known issue. Otherwise I’ll work on a minimal example that reproduces the error.

2

Nevermind, I just found the error.
I spotted it incredibly fast after I wrote the message here (while I was struggling with it for a few hours before asking for help).

The problem was that I had an html element of the layout of the new page with the same id as one on the other page.
So I guess the problem was that a callback was trying to update the same element (not sure about it). Anyway changing the id fixed it.

The fact that no error message is thrown makes it very difficult to debug. I guess this is because of dash_app.config.suppress_callback_exceptions = True. Is there a way to make multipage work and still get error messages?

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