Horizontal Scroll when a user accepts Admin invitation to join a subwiki

Steps to reproduce:

• from the main wiki, create a username
• create a Subwiki called "Workspace Request Join" and set it to "Only an admin is allowed to invite users"
• invite the user you created earlier
• login to the user, and accept the invitation
• go to main wiki on Main.WebHome.
• you will see that the message written generate a horizontal scrollbar

The problem is with the following CSS rule in Main.Activity :

.activityList .message {
    white-space: pre;
}

Image attached