diff -urp advanced_forum/advanced_forum.module advanced_forum-modif/advanced_forum.module
--- advanced_forum/advanced_forum.module	2008-06-10 05:21:48.000000000 +0200
+++ advanced_forum-modif/advanced_forum.module	2008-08-24 11:10:10.000000000 +0200
@@ -104,7 +104,21 @@ function advanced_forum_settings_page() 
     '#description' => t('Choosing yes causes advanced forum to consider every comment a forum comment and attempt to theme it that way. Some changes to your theme may be required.'),
     '#default_value' => variable_get('advanced_forum_theme_all_comments',0),
   );
-
+  //collapsible container
+  $form['advanced_forum_collapse_settings'] = array(
+    '#type' => 'radios',
+    '#title' => t('Choose collapse state'),
+    '#options' => array(t("All collapsed"), t("None collapsed")),
+    '#description' => t('Choose initial collapse state of the forums.'),
+    '#default_value' => variable_get('advanced_forum_collapse_settings', 0)
+  );
+  $form['advanced_forum_collapse_icons'] = array(
+    '#type' => 'radios',
+    '#title' => t('Use icons?'),
+    '#options' => array(t("Yes"), t("No")),
+    '#description' => t('Choose to use icons or not.'),
+    '#default_value' => variable_get('advanced_forum_collapse_icons', 0)
+  );
   // Send our form to Drupal to make a settings page
   return system_settings_form($form);
 } 
diff -urp advanced_forum/themes/advforum/advanced_forum.css advanced_forum-modif/themes/advforum/advanced_forum.css
--- advanced_forum/themes/advforum/advanced_forum.css	2008-05-28 23:03:07.000000000 +0200
+++ advanced_forum-modif/themes/advforum/advanced_forum.css	2008-08-24 11:10:10.000000000 +0200
@@ -58,6 +58,10 @@
   color: white;
 }
 
+#forum .container span, .container img { /*collapsible forum*/
+	cursor: 	pointer; 
+}
+
 #forum td.container a { 
   font-weight: bold;
   color: white;
diff -urp advanced_forum/themes/advforum/advanced_forum-structure.css advanced_forum-modif/themes/advforum/advanced_forum-structure.css
--- advanced_forum/themes/advforum/advanced_forum-structure.css	2008-05-28 23:03:07.000000000 +0200
+++ advanced_forum-modif/themes/advforum/advanced_forum-structure.css	2008-08-24 11:10:10.000000000 +0200
@@ -48,6 +48,11 @@ td.forum {
   line-height: 1.2;
 }
 
+#forum .container span, .container img { /*collapsible container*/
+	margin:		0 1em 0 0; 
+	float:		right;
+}
+
 #forum .description {
   padding-left: 0px;
   margin-left: 0;
diff -urp advanced_forum/themes/advforum/advf-forum-list.tpl.php advanced_forum-modif/themes/advforum/advf-forum-list.tpl.php
--- advanced_forum/themes/advforum/advf-forum-list.tpl.php	2008-05-13 06:15:55.000000000 +0200
+++ advanced_forum-modif/themes/advforum/advf-forum-list.tpl.php	2008-08-29 19:22:03.000000000 +0200
@@ -30,7 +30,71 @@
  * @see template_preprocess_forum_list()
  * @see theme_forum_list()
  */
+
+//collapsible container jQuery
+jquery_plugin_add("cookie");
+$containerN = 0; //There are N containers
+
+foreach ($forums as $child_id => $forum) //count containers
+	if ($forum->is_container) $containerN += 1;
+
+//This mess is done, because this is inline jQuery with html <img> tag. XHTML does not allow <img> tags in inline jQuery.
+if(variable_get('advanced_forum_collapse_icons', 0) == 0) //0 if collapse icons are used, else text.
+{
+	$hide = '$("img#containerMode-COUNTER").attr("src", "sites/all/modules/advanced_forum/themes/advforum/images/minimize.gif")';
+	$show = '$("img#containerMode-COUNTER").attr("src", "sites/all/modules/advanced_forum/themes/advforum/images/maximize.gif")';
+}
+else
+{
+	$hide = '$("#containerMode-COUNTER").text("hide");'; //hide string - COUNTER will be replaced
+	$show = '$("#containerMode-COUNTER").text("show");';//show string - COUNTER will be replaced
+}
+
+for ( $counter = 1; $counter <= $containerN; $counter += 1)
+{
+	if(variable_get('advanced_forum_collapse_settings', 0) == 0) //if zero then collapse, else don't collapse.
+		//create Set Cookie string, which containers to collapse as default
+		$jQSetCookie .=
+		'if($.cookie("container'.$counter.'") !== "expanded")
+			$.cookie("container'.$counter.'", "collapsed");
+		'."\n\t";
+	//create the toggle string
+	$jQtoggle .='$("#containerID-'.$counter.'").click(function(){
+		$(".forum-child-'.$counter.'").toggle()
+		if($.cookie("container'.$counter.'") !== "collapsed")
+		{
+			$.cookie("container'.$counter.'", "collapsed");
+			'.str_replace("COUNTER", $counter , $show).'
+		}
+		else
+		{
+			$.cookie("container'.$counter.'", "expanded");
+			'.str_replace("COUNTER", $counter , $hide).'
+		}
+	});'."\n\t";
+	//create the cookie string
+	$jQcookie .= 
+		'if ($.cookie("container'.$counter.'") == "collapsed")
+		{
+			$(".forum-child-'.$counter.'").hide();
+			'.str_replace("COUNTER", $counter , $show).'
+		}
+		else
+			'.str_replace("COUNTER", $counter , $hide).'
+		'."\n\t";
+}
+
+drupal_add_js ( //include the jQuery stuff, don't know if this is the correct place to put this?
+'
+$(document).ready(function() 
+{
+	'."$jQSetCookie$jQtoggle$jQcookie".
+	'return false;
+});',
+'inline'
+);
 ?>
+
 <table id="forum-<?php print $forum_id; ?>">
   <thead>
     <tr>
@@ -44,6 +108,7 @@
   <?php 
   $num_forums = count($forums); 
   $forum_num = 0;
+  $container = 0; //collapsible container
   ?>
   <?php foreach ($forums as $child_id => $forum): ?>
     <?php 
@@ -59,11 +124,12 @@
       default:
         $position = 'middle_row';
     }
+    if ($forum->is_container)$container += 1;//collapsible container
     ?>
-    <tr id="forum-list-<?php print $child_id; ?>" class="<?php print $forum->zebra; ?> <?php print $position;?>">
-    <td <?php 
-        if( $forum->is_container) {
-          print 'colspan="4" class="container"';
+    <tr id="forum-list-<?php print $child_id; ?>" class="<?php print $forum->zebra; ?> <?php print $position;?> <?php if (!$forum->is_container) print "forum-child-".$container;?>"> <!-- collapsible container-->
+    <td <?php
+    			if( $forum->is_container) {
+          print 'colspan="4" class="container" id="containerID-'.$container.'"';
           } elseif ($forum->new_topics) {
             // Special class when the forum has new topics for changing icon
             print 'class="forum forum-list-new"';
@@ -76,7 +142,14 @@
                * left-margin for indenting.
                */ ?>
         <?php print str_repeat('<div class="indent">', $forum->depth); ?>
-          <div class="name"><a href="<?php print $forum->link; ?>"><?php print $forum->name; ?></a></div>
+          <div class="name"><a onclick="event.cancelBubble = true" href="<?php print $forum->link; ?>"><?php print $forum->name; ?></a> <?php 
+          if ($forum->is_container)
+          {
+          	if(variable_get('advanced_forum_collapse_icons', 0) == 0) //0 if collapse icons are used, else text.
+          		print '<img id="containerMode-'.$container.'" src="" alt="Show or hide the forum" />';
+          	else
+          		print '<span id="containerMode-'.$container.'"></span>';
+          }?><!--collapsible container--></div>
           <?php if ($forum->description): ?>
             <div class="description"><?php print $forum->description; ?></div>
           <?php endif; ?>
Only in advanced_forum-modif/themes/advforum/images: maximize.gif
Only in advanced_forum-modif/themes/advforum/images: minimize.gif