Nel template forumhome cercate:

Codice:
  <vb:if condition="$show['sidebar']"> 
        </div> 
    </div> 

    <div id="sidebar_container"<vb:if condition="$vboptions['sidebarposition'] == 0"> class="sidebarleft"</vb:if>>
        <a id="sidebar_button_link" href="#"> 
            <vb:if condition="$vboptions['sidebarposition'] == 0"> 
            <img id="sidebar_button" src="{vb:stylevar imgdir_misc}/tab-collapsed-left.png" alt="" /> 
            <vb:else /> 
            <img id="sidebar_button" src="{vb:stylevar imgdir_misc}/tab-collapsed.png" alt="" /> 
            </vb:if> 
        </a> 
        <ul id="sidebar"> 
            {vb:raw sidebar} 
        </ul> 
    </div> 
    </vb:if>
e eliminatelo.

Sempre in forumhome cercate:

Codice:
    {vb:raw forumhome_markread_script}
e aggiungete sotto:

Codice:
  <vb:if condition="$show['sidebar']"> 
        </div> 
    </div> 

    <div id="sidebar_container"<vb:if condition="$vboptions['sidebarposition'] == 0"> class="sidebarleft"</vb:if>>
        <a id="sidebar_button_link" href="#"> 
            <vb:if condition="$vboptions['sidebarposition'] == 0"> 
            <img id="sidebar_button" src="{vb:stylevar imgdir_misc}/tab-collapsed-left.png" alt="" /> 
            <vb:else /> 
            <img id="sidebar_button" src="{vb:stylevar imgdir_misc}/tab-collapsed.png" alt="" /> 
            </vb:if> 
        </a> 
        <ul id="sidebar"> 
            {vb:raw sidebar} 
        </ul> 
    </div> 
    </vb:if>
Per 4.0.x

Al posto di:

Codice:
  <vb:if condition="$show['sidebar']"> 
        </div> 
    </div> 

    <div id="sidebar_container"<vb:if condition="$vboptions['sidebarposition'] == 0"> class="sidebarleft"</vb:if>>
        <a id="sidebar_button_link" href="#"> 
            <vb:if condition="$vboptions['sidebarposition'] == 0"> 
            <img id="sidebar_button" src="{vb:stylevar imgdir_misc}/tab-collapsed-left.png" alt="" /> 
            <vb:else /> 
            <img id="sidebar_button" src="{vb:stylevar imgdir_misc}/tab-collapsed.png" alt="" /> 
            </vb:if> 
        </a> 
        <ul id="sidebar"> 
            {vb:raw sidebar} 
        </ul> 
    </div> 
    </vb:if>
Aggiungete:

Codice:
<vb:if condition="$show['sidebar']"> 
        </div> 
    </div> 

    <div id="sidebar_container"<vb:if condition="$show['sidebarposition'] == 'left'"> class="sidebarleft"</vb:if>>
        <a id="sidebar_button_link" href="#"> 
            <vb:if condition="$show['sidebarposition'] == 'left'"> 
            <img id="sidebar_button" src="{vb:stylevar imgdir_misc}/tab-collapsed-left.png" alt="" /> 
            <vb:else /> 
            <img id="sidebar_button" src="{vb:stylevar imgdir_misc}/tab-collapsed.png" alt="" /> 
            </vb:if> 
        </a> 
        <ul id="sidebar"> 
            {vb:raw sidebar} 
        </ul> 
    </div> 
    </vb:if>
Fonte: vB.org