It’s a text zooming issue. My bad. My browser’s font is set to “very large”.
Additionally, I added plain-text content. The plain-text content is also not displayed in the 2nd and 3rd tabs.
Up your memory limit. Write in wp-config.php file following code:
define(“WP_MEMORY_LIMIT”, 256);
It may not be enough. The more people who use your chat, the more taxing it’s going to be on the server. Maybe after you get just 30 users chatting simultaneously, it’s going to slow down again.
