I picked collaps-o-matic which I liked most and its easy to work with.
Now that the project is life I found out that some expand-injections are not displayed on Chrome & Safari.
There are 12 expands, most are similar in the same list. 3, 7, 8,9 do not show up. Two more on the same side are invisible at Chrome + Safari while FF shows them.
I use the simple version within a list: all are same: [expand] [/expand].
So this is a bit confusing and a little testing around did not bring success.
Thanks for support. If more details are requested please let me know. The project is private so I can´t service the url.