Greetings. This one is there for a long time, so I hope it can be addressed. When playing Jass with 4 players, when one is supposed to choose a trump suit pressing enter on a card plays it and selects it as a trump. This isn't a huge problem, but it can make the game unplayable. If you have for example played the ace of hearts, if someone has no higher card the Playroom will still tell them they can't undercut making the game completely blocked. They can't obviously play another suit because then it says that you must follow. This is something I've experienced a few times when teaching the game to new players who can sometimes press enter in the beginning by mistake. I suggest therefore that if you must select a trump suit, pressing enter on a card simply opens the trump selection menu, same as the A key.
Note: You won't be able to reproduce this bug if your partner let's you choose the trump suit, since in that case it isn't your turn so you can't play a card. This only happens when you are the first one to choose the trump.

Hello,

This isn't a bug but was intentional. When playing in real life, usually the first player enters with trump; the jack if he has it, or his best card in case his teammate chose for him.

Talking of which, in apples in the first trick if you don't have the suit card, you have to cut somewhat similar to belote.

Hello. I am reviving this topic to clarify my bug report. I have not replied because I wanted to make sure to replicate the correct situation and describe the bug accurately. The problem occurs when you try to play the jack without choosing the trump first. So here I have the situation as follows: In my hand Jack, nine, queen and 6 of hearts. If I play the jack, my opponent cannot do anything because the game says he isn't allowed to undercut. He has in his hand 7, 10, king and the ace of hearts. In this case the game is completely stuck. I have try to save and restore and it did not help. Additionally, I have tried to kick the player to see if the bot would do anything, but in that case I get Error #3003 ! Si le problème persiste, veuillez quitter cette table et en recréer une nouvelle / If the problem keeps happening, please leave this table and recreate a new one

It happened something similar when I played jass with Aurel and some bots.
I had to save the table, but one bot played 6 of trump.
When I restored that game on the next day, I played jack of trump and Aurel could not play any of his trump cards. He had 8 and queen of trump and got the same message that he was not allowed to undercut.
I saved the table and restored, but it still did not work and we had to leave, although there was not any message like it happened in that case mentioned by you Nikola.

That is not the only issue, I let my teamate choose a trump and there was no response so I played a jack of clubs and clubs became the trump suit for that round.