This is a small plugin for the ForumActif toolbar which adds a quick login form to the toolbar. So instead of being taken to a new page to login, it'll bring up a small popup instead. To install this module, simply go to your Admin Panel then Modules > JS codes management and create a new script with the following settings.
Title : fa_toolbar_login
Placement : In all the pages
Then paste the raw source into the textarea and submit. There's no need to install the CSS since it's already included in the script, but you can remove the write and add the CSS to your sheet instead if you want.
For a more indepth tutorial please see the following link(s).
Once the installation is finished the result should be similar to the following image, aside from the toolbar style.