@Lefteris

The problem occurs when the Multilingual is active only.

To see the problem just download Joomla 3.4 install it and activate 2 different languages.

Install k2 only and the problem is generated without any other extensions.

Create an article / edit an article and this alert print on video (pop up allert)

Mine was in my template. I assigned a blank template to the K2 Menu item and it solved the issue.

I got the same solution.
I had a multilanguage site with Greek and English in J3.3.6 and K2 v2.6.9 and everything was ok with "multilanguage status" module enabled.
I updated to J3.4 and i started getting the message.
I disable the "multilanguage status" module, and now the problem is gone.

Hello,

I also disabled the "Multilanguage status" module and the error is gone.

regards
Ronald

Thank you for your feedback Ronald :)

I cannot verify the issue yet. For me everything works fine.

@Giancarlo Agrati

Can you provide more details on this or the exact steps you took? I just made a fresh install of Joomla! 3.4, enabled two languages, enabled the multilingual status module and installed K2 and everything keeps working fine for me.

I can confirm this fixes the issue for me. I have a site with en-GB and zh-TW. Using the ISIS template on the backend. Tried disabling all manner of extensions to no avail.

Issue:
Open any K2 item and just before the item paeg is rendered, get the javascript alert "Item must have a title".

Go to Module Manager, display Admin modules, disable Multilanguage Status, confirm the alert does not occur.

Using Joomla 3.4, K2 2.6.9, Gantry 4.1.28, RT Iridescent theme 1.1, a bunch of misc extensions.

Cheers
Paul

Disabling multilanguage status solved it for me also.

@Lefteris

My site is an upgrade site starting with J2.5 up through all the versions to J3.4 if that helps. The problem only appeared after the upgrade from 3.3 to 3.4.

Paul

More info on this issue:

If I go to Extra Fields,
click on New
I get the message "Please select a group or create a new one".

With Multilanguage status module unpublished this message does not appear.

I am sorry but I do not understand you.
Is the problem solved or is it still present?