As there was no fix in the current version and hotfixes I tried to reproduce my error and succeeded easily.
I simply poked myself with TS3 and it worked the first time as it shows this little popup in the server tree, but still doesn’t open a chat in server tab section, chat opened as is started a private chat.
Afterwards I switched to another server which I was already connected to and made a second attempt. This time none of my 7 pokes showed up in any way. Just like the first time I opened a private chat and expected to finally see something in server tab section.
Something happend indeed, but it was the chat from my first attempt on another server and another id that popped up in server tab section.
I was simply not able to let any other chat appear in server tab section then the one from my first attempt.
It seems kinda broken to me and really a bit odd, hope there’ll be a fix for this issue.