There is no style specified for the tooltip when hovering over the "U" and "O" icons in rsgallery2 1.14.3. Makes it pretty hard to see the info. Added the following to components/com_rsgallery2/templates/semantic/css/template.css:

.tool-tip{
    background-color:#ffffcc;
    border: 1px solid black;
    padding: 2px;
}

Solves the problem. Change to whatever colors you like.

Great, thanx!