Form with long choice list seems to overload KoBoToolbox

[Severin]

I have created a form with 4 levels of cascading list from an XLS form. The selection tab has almost 6,000 rows. I have no problem creating the form in kf.kobotoolbox.org, deploying the form and adding data to it from KoBoCollect on my phone, and the cascading lists work fine. The problem is when I try to edit the form. It’s loading all the time and Firefox tells me that the page is slowing down the computer:

It is currently using only 11GB of the 16GB RAM on my i7 running Ubuntu 24.04.

After a few minutes it displays this contradictory information:

Is the issue on the KoBoToolbox server side ? Does it struggle with complex cascading lists? Here is the form, in case you want to test it.
Form_with_cascadinglists.xlsx (185,2 Ko)

[Severin]

EDIT: It is fully loaded after 5-10 minutes. It can be edited, but sometimes there’s a flicker when you move the mouse over the form, and it’s briefly displayed like this, shifted to the left, so clicking is complicated:

[Kal_Lam]

@Severin, the system will timeout when you have such long choices under the choices tab, which I see as follows:

list_name	count
village	5290
arrondist	547
commune	78

You will need to use the external CSV file as used in these community posts discussed previously:

Cascading Limitation

@dimesh, seems like you have a lot of choices in your cascading select option. Please be informed that in such cases you will need to use the external CSV to list the choices. You could overcome this limitation as outlined in the post discussed previously (using the select_one_from_file question type): Alternatively, you could also overcome this issue by using the select_one_external question type as outlined in the post discussed previously: