Can't edit slideshow with more than 3 slides

Hi !

Test site #2 up and running. Everything works OK. Too bad it's a localhost.
Test site #1 still there, it's the one where I have the issue with editing slideshows with more than 3 slides. Localhost too.

For some highly unclear reason, there's something incompatible between my site's menu items and Slideshow CK. When I use the default menu items provided by the raw Joomla! install, Slideshow CK works fine. When I upload my old menu items from an old SQL dump, that's when I can't edit a slideshow with more than 3 slides. After carefully looking at the structure of the SQL tables, the only common point I can see is that both the menu items and Slideshow CK use JSON. But I still fall very short of understanding why the menu items would disturb Slideshow CK. I also compared the structure of the menu table on my two test sites, and they look absolutely identical. On both sites, all menus use AS Menu module. I have absolutely no clue of the interactions, if any, between AS Menu and Slideshow CK. One solution is straightforward : recreate the 900-plus Test Site #1 menu items on Test Site #2, where Slideshow CK works like a charm. But before embarking on such a huge workload, I'd like to know whether there is a smarter alternative.

Bottom line : the symptom I can see with the Slideshow CK editor looks more than the consequence of something else than a problem by itself.

Any suggestions ? Things that I should be looking for or that I could test ?

As usual, thanks a lot for your time and effort.

Hi
I don't see why the menu items would disturb Slideshow CK, especially that the problem occurs in admin and the menu items are absolutely not loaded in this area
the only problem that could be is the limit of the "params" field of the module given by the SQL field type (shall be "text")
CEd

just to be sure, you have created a full copy of Site #1 into Site #2, and it works ?

Yeah, after reading both data structures, I noticed that the params field was indeed different, mediumtext for menu items and longtext for modules, but I fail to see why this should be an issue. To be sure, I tried to modify the type, all longtext, all mediumtext, and so forth, but it did not change anything.

Not exactly. Site #1 has been my test and development site since 2012. I created Site #2 a few days ago from a raw Joomla! 3.18 install, added a few extensions which I need, JCE, modules anywhere, ZH Google Maps, AS Slider, AS Menu, vvisitcounter, Maxi Breadcrumbs CK ... and Slideshow CK, of course. Then I exported a few tables from Site #1 into Site #2 : users, categories, articles ... For the sake of common sense, I wanted to keep Site #2 as "pure" as possible, to compare both sites and determine what causes the issue as accurately as I can.

At the moment, the situation is as follows :
• Site #1, my development site for years, is complete, has all 900-plus menu items, and has the "3-slide issue".
• Site #2, the pure Joomla! 3.18 install, has all the articles and categories of site #1, only a subset of modules (including 1 test slideshow), a subset of menu items (6, so far) and works absolulety fine.

Forgot to mention above ...

I also have both menu items tables on site #2, the one from site 1 (which helps show the 3-slide issue) and the native one (which works like a charm) ... of course with different prefixes, to make sure they don't conflict each other. When table #1 is used, I can see the 3-slide issue. When table #2 is used, everything works OK. So there is "something" with that table, which I have not clearly identified so far. The only difference is the params field : mediumtext on Table #1, text on Table #2. So I tried to change params from mediumtext to text on table 1 and I still have the issue. I also tried the obvious : restart the server, restart SQL, clear browser cache .. to no avail. Situation unchanged, 3-slide issue on #1, works OK on #2.