Issue #76 manual test

• make sure that entire editor is visible in browser viewport,
• click on the First link and check if balloon panel appeared on bottom of the selection,
• close panel, click on the Second link and check if balloon panel appeared on bottom of the selection,
• close panel, click on the Third link and check if balloon panel appeared on top of the selection,
• close panel, scroll page to the SCROLL HERE marker, click on the Third link and check if balloon panel appeared on bottom of the selection.