In the Mana web app, you can react to a chat message with an emoji without sending a new message.
How to react to a chat message
To react to a chat message in Mana, open the conversation that contains the message.
Right-click the message you want to react to.
Choose a reaction:
Select one of the quick reactions shown at the top of the message menu.
Or select +, then select an emoji from the full reaction picker.
Your reaction appears beside the message without opening another page.
Remove your reaction
For a quick reaction, right-click the message and select the same emoji again. For a reaction chosen from the full picker, select the reaction beside the message, then select your reaction in the Reaction panel.
When reactions are not available
If reactions are not shown in the chat message menu, they are not available for that message.