Ok, some new info: I do think the problem is indeed CSS bases:
In the CRP settings I have css. When I remove all the CSS from the CRP settings, the sharebuttons container no longer is too large. So the question is, which css setting causes the error in firefox and chrome, see below for the css in CRP settings:
#crp_related ul {
list-style: none;
float: left;
margin: 0px 0px 0px -46px ;
}
#crp_related li, #crp_related a {
float: left;
overflow: hidden;
position: relative;
text-align: center;
}
#crp_related li {
margin: .04em;
border: 0px solid #ddd;
padding: 6px;
}
#crp_related a {
width: 150px;
height: 150px;
}
#crp_related a:hover {
text-decoration: none;
}
#crp_related img {
max-width: 150px;
margin: 0px 0px 0px 0px ;
-webkit-border-top-left-radius: 10px;
-webkit-border-top-right-radius: 10px;
-webkit-border-bottom-left-radius: 10px;
-webkit-border-bottom-right-radius: 10px;
-moz-border-radius-topleft: 10px;
-moz-border-radius-topright: 10px;
-moz-border-radius-bottomleft: 10px;
-moz-border-radius-bottomright: 10px;
border-top-left-radius: 10px;
border-top-right-radius: 10px;
border-bottom-left-radius: 10px;
border-bottom-right-radius: 10px;
}
#crp_related .crp_title {
position: absolute;
height: inherit;
bottom: 6px;
left: 6px;
padding: 3px;
width: 144px; /* = 150px – (3px * 2) */
color: #fff;
font-size: .9em;
text-shadow: #000 .1em .1em .2em;
background: rgb(0.5, 0.5, 0.5);
background: rgba(0, 0, 0, 0.5);
-webkit-border-bottom-left-radius: 10px;
-webkit-border-bottom-right-radius: 10px;
-moz-border-radius-bottomleft: 10px;
-moz-border-radius-bottomright: 10px;
border-bottom-left-radius: 10px;
border-bottom-right-radius: 10px;
}
#crp_related li:hover .crp_title {
color: #EE97CC;
background: rgb(0.2, 0.2, 0.2);
background: rgba(0, 0, 0, 0.8);
}