Message kept in the "sending" state

Hi,

I started using Mattermost with my team today. It seems like a great tool, however I already encountered a bug.

I was typing a message, and when I clicked "send", the message went into the "sending" state (with the little loading animation on the right), but the message seemed to be stuck there. I reloaded the page, and then my message was duplicated, once in the "sent" state and the other one still in the "sending" state.

I tried to clear the cache, reload the page, even restart the server with no success so far. What can I do to remove the message in the "sending" state ?

Thank you !