Thanks for your reply. I tried putting $SidebarWidgets in the SideBar.ss code as you recommended, but the rss widget does not appear on my page. When I place $SidebarWidgets in the Page.ss (/templates/Page.ss), directly under $Layout, the rss widget appears, in the sidebar, but underneath the sidebar menu, so it doesn't have the nice formatting of the sidebar menu, it's just plain links. If I remove $SidebarWidgets from the Page.ss code, it disappears. No matter where I place it in the SideBar.ss code, it doesn't make the widget appear. Looking at the layout.css, I see the #Sidebar section, but I don't know what I should modify in there.
I'm trying to use WidgetManager but the widgets does not show on front page :( I already try it with different themes, blackcandy, itheme, simplestripe, etc. Is there any problem with widget manager and SS 2.4.6 ?
How can I debug this?
ps. I'm not a real developer :(