Layout a due colonne - problemi

[shishii]

Ciao a tutti,

ho il sito con un layout a due colonne classico:

http://www.shishii.com/dummy/index.php

ma in alcuni casi si produce uno strano effetto, cioè parte della colonna sinistra viene "inghiottita" dal footer, ad es:

http://www.shishii.com/dummy/index.php?id=31

come vedete parte dei bottoni scompaiono sotto il footer. Ciò avviene quando il complesso degli elementi presenti a sinistra occupa più spazio verticale di quelli della colonna principale centrale.

Non capisco perchè ciò avviene.

Questo è il css che uso:

html,body{
	margin:0; 
	padding: 0;
	height: 100%;
}
body {
	background-image: url(../img/background-4.gif);
	text-align: center; /*centra in IE 5.x */
	font-family: verdana, "comic sans ms", arial, sans-serif;
	font-size: 80%;
}
DIV#container {
	 width: 770px;
   margin: 0px auto;   /*centra negli altri browsers*/
   text-align: left;   /*ripristina l' allineamento*/
   position: relative;
   height:100%;
   color: #000000;
   background-color: #f7f7f7;
   background-image: url(../img/background-menu.gif);
   background-repeat: repeat-y;
   background-position: left top; 
}
body>DIV#container{
	height: auto; 
	min-height: 100%;
}

TD { font-size: 80%; }
H1 { font-size: 2.3em; }
H2 { font-size: 1.5em; }
H3 { font-size: 1.2em; }
P, H1, H2, H3 {margin: 0px 0px 5px 0px;}
A {color: blue; text-decoration: none;}
A:hover {color: red; text-decoration: underline;}
PRE, CODE {
	font-family: "courier new", courier, monospace;
	background-color: #e2e2e7;
}
.dt {
	font-weight:bold;
	color: black;
}
.sintassi {
	color: red;
}
.evidence {
   font-weight:bold;
	color: black;
}
.tt {
	font-family: "courier new", courier, monospace;
}
.small {
	font-size: 0.9em;
}
.sito {
	color: green;
}
.banner {
	vertical-align: top;
	position: absolute;
	right: 10px;
}
.title {
	width: 600px;
	padding-top: 10px;
}
.subtitle {
	width: 600px;
	background-color: #e2e2e7;
	margin-left: 20px;
	margin-top: 2px;
	padding-top: 1px;
	padding-bottom: 1px;
	padding-left: 1px;
	padding-right: 1px;
}
.time {
	width: 600px;
	padding-left: 20px;
}
.datetime_cr {
	padding-left: 60px;
	font-style: italic;
}
.datetime_mod {
	padding-left: 8px;
	font-style: italic;
}
.oratime {
	font-style: italic;
}
.newsletter {
	padding-left: 188px;
}
.cerca {
	padding-left: 24px;
}
.contatto {
	padding-left: 24px;
}
.feedrss {
	padding-left: 24px;
}

#ephemeridis {
	text-align: center;
	background-image: url(../img/sand-light.jpg);
	width: 310px;
	margin-left: 10px;
	float: right;
	padding-top: 0px;
	padding-bottom: 0px;
	padding-left: 10px;
	padding-right: 10px;
	
	border-right-width: 2px;
	border-right-color: gray;
	border-right-style: inset;
	border-bottom-width: 2px;
	border-bottom-color: gray;
	border-bottom-style: inset;
}
.ephecorpo {
	font-size: 0.8em;
	font-style: italic;
	text-align: justify;
	text-indent: 15px;
}
.ephefonte {
	font-size: 0.7em;
}

/* Header 1 column */
#header_1 {	
	vertical-align: top; 
	background-color: #80ACFF;
	padding-top: 5px;
	padding-bottom: 5px;
	padding-left: 10px;
	padding-right: 10px;

}
#header_1 DIV A {	
	color: #eeeeee;
	text-decoration: none;
	font-weight: bold;
	font-size: 15px;
}
#header_1 DIV A:hover {
	color: red;
	text-decoration: none;
	font-size: 15px;
	font-weight: bold;
}
#sub_header_1 {
	/*width: 230px;*/
	vertical-align: top;
	text-align: left;
	padding-bottom: 5px;
}
#sub_header_2 {
	/*width: 540px;*/
	vertical-align: top;
	text-align: center;
}
#sub_header_3 {
	border-top: 1px solid #eeeeee;
	border-bottom: 1px solid #eeeeee;
	border-left: 1px solid #eeeeee;
	border-right: 1px solid #eeeeee;
}

/**********************************/
/* contenitore della colonna sinistra */
#menu {	
	vertical-align: top; 
	width: 120px;	
	padding-top: 10px;
	float: left;
}
/* Menu 1 column */
#menu_1 {	
	vertical-align: top; 
	width: 120px;	
	/*background-color: #80ACFF;*/
	padding-top: 10px;
	/*float: left;*/
}
#menu_1 DIV {
	width: 95%;
}
#menu_1 DIV A {
	color: black;
	text-decoration: none;
}
#menu_1 DIV A:hover {
	color: red;
	text-decoration: underline;
}

/*  MENU 1, level 1, normal state (NO) */
#menu_1 DIV.menu1-level1-no {
  border-bottom: 1px dotted #999999;
  padding-top:5px;
  padding-left:5px;
}
/*  MENU 1, level 1, active state (ACT) */
#menu_1 DIV.menu1-level1-act {
  font-weight:bold;
  padding-top:5px;
  padding-left:5px;

  background-color: #eeeeee;
  /* valido solo per IE e non per W3C
  FILTER: alpha(opacity=70,style=1);*/
}
#menu_1 DIV.menu1-level1-act A {
  color:black;
}

/*  MENU 1, level 2, normal state (NO) */
#menu_1 DIV.menu1-level2-no {
  font-size: 0.9em;
  padding-left:15px;
}
/*  MENU 1, level 2, active state (ACT) */
#menu_1 DIV.menu1-level2-act {
  font-size: 0.9em;
  font-weight:bold;
  padding-left:15px;
}
#menu_1 DIV.menu1-level2-act A {
  color: #eeeeee;
}

/*  MENU 1, level 3, normal state (NO) */
#menu_1 DIV.menu1-level3-no {
  font-size: 0.8em;
  padding-left:20px;
}
/*  MENU 1, level 3, active state (ACT) */
#menu_1 DIV.menu1-level3-act {
  font-size: 0.8em;
  font-weight:bold;
  padding-left:20px;
}
#menu_1 DIV.menu1-level3-act A {
  color: #eeeeee;
}

/**********************************/
/* bannerLeft */
#bannerLeft {
/*float: left;*/
width: 120px;
position: relative;
top: 0px;
left: 0px;
text-align: center;
}

/**********************************/
/* Corpo 1 column */
#content {	
	vertical-align: top;
	width: 630px;
	text-align: justify; 
	line-height: 1.4;
	/*background-image: url(../img/background-5.gif);*/
	padding-top: 10px;
	padding-bottom: 10px;
	padding-left: 10px;
	padding-right: 10px;
	margin-left: 120px;
}

#content DIV.lastupdate {
  font-size: 0.8em;
  line-height: 150%; 
  text-align: left;
  color : #003366; /*dark blue */
}
#content DIV.class-totop {
  font-size: 0.8em;
  font-weight:bold;
}
#content DIV.class-totop A {
  color: black;
  text-decoration: none;
}
#content DIV.class-totop A:hover {
	color: red;
	text-decoration: underline;
}

/**********************************/
#footer {
	background-color: #80ACFF;
	/*position:absolute;
	bottom: 0;*/
	width: 100%; /* necessario se si vuole il footer sempre a fondo pagina
	ma da altri problemi */
	clear: both;
}
#footer P {
	font-size: 0.9em;
	text-align: center;
}