The problem has been fixed and the fix will be included in Layouts 1.9.
There are too many affected files for a simple patch and so a hotfix is being prepared and should be available soon, and I will update here when it is.
The fix has been published as a Layouts update to version 1.8.6
Keep an eye out for an update notification on your plugins page.
If that doesn't appear or you don't want to wait you can download the zipped plugin file from your downloads page (wp-types.com/my-account/downloads). You can use the Upload button on the Add New Plugins page to add the zipped version of Layouts to your site, but that requires deleting the old plugin first.
If you have FTP access you can upload the unzipped file to your plugins folder and overwrite the old plugin version.
Please re-test the issue and let me know if you have any continuing problems.
I was looking forward to the 1.8.6 update, since I am having the same problems.
Unfortunately it didn't solv the problem.
I attach a class to a row/element, save it, want to enter another element and get the classes shown from the element before that.
Besides other issues like getting a drop down instead of a text field to enter classes with a handful of classes in the dropdown but no possibility to add one I haven't used before.
So it is still broken for me. This is a huge issue to be honest. I will now try to rollback the layouts version until this issue is solved
Could you double-check that you have updated the plugins?
I just set up a fresh WordPress test site with the latest versions of Types (2.2.2), Views (2.2.1) and Layouts (1.8.6) plus the twentysixteen integration plugin which generated the basic layouts.
I edited the layout for posts and added two rows, to which I added a series of classes (test-1-a, test-1-b etc. to the first row and test-2-a, test-2-b etc. to the second row).
I saved the layout, viewed the hello world post on the front end and inspected the source and the classes were correctly added.
I went back in and edited the rows in the layout and the classes were there as expected.
I repeated to double-check, and I couldn't find the problem.
If you are still having problems, please open a new thread so I can deal with you directly there (you are welcome to assign the ticket to me when you do).