'Slider' option on events grid

Hi all,

I have sent up an Collision “grid” of indico items, for the upcoming 7 days for wlcg-test-cern.web.cern.ch

However I would like the ‘sliding’ effect that you have on home.cern to view more events:

How did you get that effect? Mine only has a ‘1 - 2’ or ‘Next’ option (whether I use full pager or mini pager) instead of the side arrows, which upon clicking reloads the entire page and sends the user back up to the top (which is not useful). it is also missing some of the styling you have on home.cern (collision effect, as well as the sliding effect).

What am I doing wrong?

Hi Cath
Happy New year.
How many items do you have ? Because the mini pager appears if you have more than X items,…
Please try to add some fakes ones and test…
If the problem persists please tell me…

Hi Almudena!

I current have 6 items in there, so the pager function is triggering.

It’s just not the same pager function (“Next” or “1-2” rather than side arrows), and the slide action doesn’t work (it just makes the page reload and puts user back at the top of the page), nor does the little collision effect of the grey/orange dots trigger.

I suspect I’m missing a library of some sorts that activates that. Incidentally, I am not using the CERN Landing Page, I wonder if that’s the container that needs to be there? (Which in itself is a problem, as I can’t install it due to ‘missing dependencies’, there’s another ticket open about that in the forum…)

Thanks :slight_smile:

BTW here’s the view setup. I’ve messed around with the pager settings to have every single possible permutation allowed there, but it’s just not working like how it does on home.cern:


Hi Cath
Ok, I can see with the web team if this a new problem.
In any case I can share with you the collision view that I have created in a landing page and it works…
If it can help you in the meantime…


Thanks Almu! :slight_smile:

Funny you can only see 3 items! That is odd.

I had to set it to display 3 items + pager (so you see 3 items at any one time, but use ‘Next’ to view the next 3), otherwise if it I set it to “Display all” or display any number more than 3, it just turns into a grid with no slider at all.

Interestingly, I have the same set-up on a site using the CERN Landing Page with a section holding it; the Collision works fine.

I am starting to suspect that this View needs to be held on the CERN Landing Page to work correctly…


Hi Cath again
After discussion with the web team, we can suggest to install the JQuery modules which will hopefully fix that issue till we include owlcarousel in cern theme or cern base.
Start with ONLY jQuery UI and then see if you need the others.


Tell us if it works


Nope, unfortunately it hasn’t worked at all! That’s a shame, I was hoping this was the ‘missing’ library!

No matter how I set up the Pager settings (whether pager or not, 10 items or 3), there are no action arrows, no ‘slider’ action, no ‘collision’ animation, and I’ve also lost the grey line holding the collision dots. There are 6 items in the list (now currently set to ‘display all’, where it has turned into a grid, same outcome as when it’s “Mini-Pager, Show 6”) so there are enough items in there to be manipulated.

I’ve cleared caches, double-checked my settings according to Collision of Events | Drupal @ CERN, now got the Jquery modules activated… no change in my Collision view :frowning:

Frustratingly, this works perfectly on the homepage of https://dphep.web.cern.ch/ where I don’t have any JQuery activated, but - in contrast - it is held by the CERN Landing Page.

Over to you… :wink:

Thanks Cath for all theses test, the web team will continue with the investigation.
I will notify as soon as we have a solution, sorry and thanks for your patience.

Hi Cath,

I don’t know if the collisions work only within the landing page. But if you have time and you want to test this do the following:

  • Create a clone site in order to not mess up the current one.
  • Enable the CERN section module.
  • Go to Custom block library and create a new custom block.
  • Add a new field entity reference and then select Paragraph.
  • Check the Section in the paragraph field.
  • Create a new block of this block type and add your collision view in the field
  • Add this block to appear in the page that you want and check if collisions work.

Hi Sotirios,

Unfortunately enabling CERN Section module is not possible, as CERN Section seems to require CERN Hero Header, and this happens when I OK to enable:

:confused: This is also very similar with what is preventing me from enabling the CERN Landing Page module as well…


Ok something has messed up the installtion of the landing page and components modules. How did you try to enable the landing page module in the first place?

Hi Cath,

Could you please create a clone of your site so I can try to fix the error there and see that it works fine?



Hi @sboutas and @paevange

This CERN Section/Hero issue is not limited to this website, I have encountered it on a couple of other new/fresh installations since November (see also this forum post). I’ve done done workarounds (ie. just stacked blocks), given I understand a centralised fix is coming. However with the refreshed WLCG site, the landing page module would be very useful to have…

How did you try to enable the landing page module in the first place?

Via the normal channel of …/extend and selecting CERN modules. Both all modules in one go, and when that failed, went one-by-one+save to find out where the blockage was. It’s Landing Page, Section and Hero header.

Here’s the clone site to use as a sandbox: https://wlcg-test-clone.web.cern.ch

Thanks! :slight_smile:

Hi @noble

I applied the fix in https://wlcg-test-clone.web.cern.ch/

Could you please check that works fine, you haven’t missed any content etc?

Thanks :smiley:


Hi @paevange

It hasn’t worked at all, I’m afraid. In fact we’ve lost even more formatting and I am now faced with “The website encountered an unexpected error. Please try again later.”

I found that my indico events views had vanished, so I rebuilt the one for the homepage.

Also the “agenda card” display mode for indico events content type had undone itself, so I put that back together.

In the brief moment I saw the homepage block (before I realised “agenda card” had undone itself), there was still no formatting of the Collision box - it was still single grey dots over elements, no slider, no grey ‘slider’ line…

And now it’s just “The website encountered an unexpected error. Please try again later.” and I’m not sure what to do now…


Hi Cath

I am just following up on this thread to check whether a solution has been found?


Hi @joachim !

Not quite yet - I’ve only just got my non-prod website back this morning in order to restart working on this (lost it all earlier this week…).

I’m also going to try creating a new website just to see if that works, as gut feeling says there is a problem with the underlying wlcg.web.cern.ch configuration (so clones tend to copy the same issue).

Will keep you posted, and thanks for checking in :slight_smile: