I think I solved the problem. It seemed to be like Andrew suspected. Here is my code:
}
#pp_tabs a {
display:block;
margin:0;
padding:0 10px;
line-height:20px;
text-decoration:none;
text-transform: none;
}
#pp_tabs ul ul {
display:none;
position:absolute;
top:19px; /* match line height for #pp_tabs a + 1*/
left:0;
float:left;
width:140px;
z-index:90;
line-height=20 and top was initially at 21. I changed “top” to 19 and since then I have no problems with the dropdownmenue.