When opening widget tab - I receive a warning

[lvandeemter]

I just re-started a website for a client of mine. This site have never been on-air, now they want to change the site and create it further. It is build with X-theme and Cornerstone. I upgraded to the latest version of the X-theme. (I would very much like to upgrade to Pro - but I think, that is not what I can do at this point because of the warning) It all seemed to work oke, until I wanted to open the tab Widget in Dashboard / Instellingen.
I receive this following warning:
Warning: array_search() expects parameter 2 to be array, null given in /public/sites/www.praktijklichterleven.nu/testsite/wp-includes/widgets.php on line 1326

On the front site everything seems to be oke. But something goes wrong… I don’t know what.

I did not do anything different to other sites I created. There are no strange plugins… And I de-activated them all, but the warning was still there.

Could you advise in this what to do? Before updating the warning was not there.

Thank you very much!

This is what the line 1326 says:

[Joao]

Hi There,

The easiest solution is to select light integrity and customize the navbar and the footer to be black.

You can add a dark background on Cornerstone to your pages instead of a white one.

Please switch to integrity light and point the placed you want to fix to be darken again.

Hope it helps

[lvandeemter]

I guess, this is not the answer to my question? Perhaps a mistake?

And I use Icon.

It is not about white / black: it is about the widget tab.

[basanta]

hi There,

Thanks again for the update!
We are really sorry for the confusion! As per your description above, it seems there is some issue with the installation.
Can you please re-install the WordPress and the theme again.
Just go to Dashboard -> Updates and click on re-install button.

Delete the theme files and re-install a fresh copy.

Let us know if that helps!

Thanks