Huge slowdown in Slack

[majutsushi]

Hi,

we're using Slack for internal chats in our company. However, I noticed that the text input gets increasingly slower the more text is in the input field. After typing a few words each new character takes several seconds to actually appear, during which Firefox uses a lot of CPU. Disabling TextareaCache Lite immediately fixes the issue.

In case it is relevant, this is how the input is defined:

<form id="msg_form" class="offline" onsubmit="TS.view.submit(); return false;" data-qa="message_form">
(lots of divs for styling and such)
</form>