Hola... Listo aqui un ejemplo que reproduce mi problema...
Código:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<!-- This file generated using Python HTMLgen module. -->
<HEAD>
<META NAME="GENERATOR" CONTENT="HTMLgen 2.2.2">
<TITLE></TITLE>
<style type="text/css">
<!--
.contenedor_conceptos{
width: 100%;
height: 43%;
white-space:normal;
background: WHITE;
}
.pedicion_conceptos{
width: 50%;
height: 39%;
background: #FCFCE6;
margin: 5pt;
visibility: hidden;
}
div.pedicion_conceptos h4{
position : relative;
left: 2pt;
text-align: left;
}
.bconceptos{
left: 120pt;
width: 40pt;
height: 10pt;
cursor: default;
bottom: 15pt;
position: absolute;
}
div.bconceptos:hover{
background: #E1E1C2;
}
.bconceptos1{
left: 200pt;
width: 40pt;
height: 10pt;
cursor: default;
bottom: 15pt;
position: absolute;
}
div.bconceptos1:hover{
background: #E1E1C2;
}
.grid {
border:1px solid gray;
}
.gridHead {
height:1em;
background-color:#E6E6E6;
font-weight:bold;
}
.gridHead td {
border:1px silver outset;
}
.gridFoot {
height:1em;
background-color:#E6E6E6;
font-weight:bold;
}
.gridFoot td {
border:1px silver outset;
}
.gridBody {
overflow:scroll;
overflow-x:hidden;
border-bottom:1px solid gray;
}
.gridBody td {
border-top:0px;
border-right:1px solid lightgray;
border-bottom:1px solid lightgray;
border-left:0px;
margin:0px;
padding:1px;
}
.gridBody tr {
background-color:white;
height: 1em;
}
.gridBody tr:hover {
background-color:#A0A0A0;
color:white;
}
-->
</style>
</HEAD>
<BODY background=BLUE>
<div class=windowBody style='width:500px;height:390px;overflow:auto;border:solid 1pt;background:GREY;' align='center'>
<FORM METHOD="POST" ACTION="conceptos.py" ENCTYPE="multipart/form-data" TARGET="workspace" NAME="conceptos">
<DIV class="contenedor_conceptos" id="grid_conceptos" style='background:BLUE;'>
<TABLE id="gconceptos" border="0" cellpadding="1" cellspacing="1" height="160px" width="100%">
<THEAD class="gridHead">
<TR>
<TD> </TD>
<TD>Concepto</TD>
</TR>
</THEAD>
<TBODY class="gridBody" id="conceptos" style="height:150px;">
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
<TR id="item_0" bgcolor="#E6E6E6">
<TD align="center" width="8%">UNO</TD>
<TD width="92%">Entrada X Ajuste de Inventario Fisico</TD>
</TR>
</TBODY>
</TABLE>
</DIV>
</BODY> </HTML>
Nota lo ejecuto con FireFox 3 beta 5. si lo ejecuto en firefox 2 no tengo problemas.
Saludos