TYPO3 Core

Maybe our attempt https://review.typo3.org/c/Packages/TYPO3.CMS/+/76877 is a possible way to go?

However, more than 4 checkboxes quickly result - especially with (customer-specific) data records.

Think, for example, of allergens contained in food, the topping of a pizza, properties of a property,...

Yes, it is possible to pack all these properties into separate fields. But then their (joint) filtering becomes more complex - and whether the UX in the backend would be better is questionable.

Wouldn't for this usecase a category tree be more helpful and workable? Or a custom rendertype even, arranging it exactly as needed?

A category tree requires a tree-like data structure. Checkboxes are at the same level.
A separate rendertype would also be a solution, yes, maybe.

Nevertheless, I question the formatting behavior of the core. In my opinion, it is broken - regardless of whether more than 4 checkboxes “make sense”.

For all $numberOfItems > 4, you'll get $colWidth <= 2 with results in CSS classes "col-sm-6 col-md-3 col-lg-2". For large screens we'll have 6 columns.

But ... There's a logic for 'colClear'-elements, too. These are inserted (for $colWidth <= 2) after each second, fourth and sixth item. With these clearers the behavior of colWidth brakes: e.g. 7 items are arranged in 6 columns, each with width 16,77%, but due to the colClear-elements the output is only two-columned.

• If a two-column layout is forced (via `colClear`), then the full width should still be used (i.e. 50% per item).
• Or - if you set the 16.77% width per item - a corresponding number of items should be arranged next to each other.

I've also recognized this behavior and think that it is not intended to interrupt the grid system with clearfixes, this way.

I think this is a relict from migration to Bootstrap.

In my opinion, the clearfixes should get removed entirely, because Bootstrap Grids doesn't work like that.

Also, it would be possible to add "col" class only for every field in palette, the Bootstrap grid will choose and align the size of each column on its own. This would also make the current calculation of column size obsolete.

For --linebreak-- a new row should be added, instead of using "dirty" clearfix.

Patch set 2 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/85556

Patch set 3 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/85556

Patch set 4 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/85556

Patch set 5 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/85556

Patch set 1 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/86918

Patch set 6 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/85556

Patch set 7 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/85556

Patch set 8 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/85556