Since a while I can not collapse layers any more. This occures randomly, somtimes they do and after a while working in a file, the layer will not collapse any more. Most of the time I can collapse them by entering isolation mode.
After multiple updates, the problem keeps occuring.
**Please note that resetting preferences will remove all the custom settings and Illustrator will launch with default settings. You can also take a backup of the folders in case you want to. Location is mentioned in the article.
I have just opdate illustrator and I did reset the preferences. And it does not work. :(. When I open a file, I can unfold or collapse some layers and then it stops working. I can only use them when I go to isolation mode.
I would appreciate it i I could be helped, because it I have been having this problem for a long time now.