Doesn't seem to happen for previews of sites.

Right now if you delete a comment it is just disappear form the comment section. I think it would be better to show a modal to the user to confirm the delete action.

Describe the bug
The title text (aka mouse over text) starts with "undefined", e.g. "undefined This user can send messages in this groupchat". I think it's supposed to be the JID, but that's unavailable in semi-anonymous groupchats.

To Reproduce
Steps to reproduce the behavior:

1. Join a semi-anonymous room as a non-moderator
2. Point at someone in the participant list
3. Wait for

I cannot reproduce this with the default usage of botui : the issue appears only when botui is part of a larger VueJS app.

When a markdown image is inserted in a message, it is immediately hidden if another message is displayed after.

botui.message.add({
	content: 'Hello World'
});
botui.message.add({
	content: 'Here is a picture : ![](https://www.google.fr/images/branding/g