Description:

When the room leader is shown in a bar by scrolling messages in a room, the tooltips triggered by header buttons at top are "eclipsed" by the room leader bar.

Steps to reproduce:

1. Open a channel containing a room leader and messages enough to vertical scrolling be present;
2. Scroll up, revealing the room leader bar;
3. Place the cursor over the any button at header (e.g. "Room Info") and wait for its tooltip.

Expected behavior:

See the tooltip entirely.

Actual behavior:

Only the top of the tooltip element is shown, hiding a half of the text.

Server Setup Information:

• Version of Rocket.Chat Server: 0.67.0-develop
• Operating System: Linux (Ubuntu 16.04 Xenial Xerus)
• Deployment Method: sources
• Number of Running Instances: 1
• DB Replicaset Oplog: enable
• NodeJS Version: 8.11.3 - x64
• MongoDB Version: 3.4

Additional context