Unable to add widgets to registered sidebar via admin; v2.6.3

I have 4 registered sidebars; Bottom-Left, Bottom-Middle, Bottom-Right, Sidebar. The register array is built in that order.

In the admin page for widgets, the default sidebar is Bottom-Left (again, in order). When I choose any of the other sidebars, click show, then click to add a widget, the widgets are only added to Bottom-Left, I can’t add a widget to any other sidebar.

Here is the register code, which looks correct to me. Any advice?


if ( function_exists('register_sidebar') ) // Sidebar Widget
register_sidebar(array(
'name' => 'Bottom-Left',
'before_widget' => '<div class="item">',
'after_widget' => '</div>',
'before_title' => '<h3 class="sub">',
'after_title' => '</h3>',
));
register_sidebar(array(
'name' => 'Bottom-Middle',
'before_widget' => '<div class="item">',
'after_widget' => '</div>',
'before_title' => '<h3 class="sub">',
'after_title' => '</h3>',
));
register_sidebar(array(
'name' => 'Bottom-Right',
'before_widget' => '<div class="item">',
'after_widget' => '</div>',
'before_title' => '<h3 class="sub">',
'after_title' => '</h3>'
));
register_sidebar(array(
'name' => 'Sidebar',
'before_widget' => '<div class="item">',
'after_widget' => '</div>',
'before_title' => '<h3 class="sub">',
'after_title' => '</h3>',
));