I see this with evolution and overlay scrollbars disabled.
I disabled overlay scrollbars with:
$gsettings set com.canonical.desktop.interface scrollbar-mode normal
(evolution:13228): Gtk-WARNING **: GtkScrolledWindow 0x7f8fa3f4faa0 is mapped but visible child GtkScrollbar 0x7f8fa409c540 is not mapped
My versions from current Ubuntu 12.10 (with proposed, updates sources enabled) ii evolution 3.6.2-0ubuntu0.1 ii libgtk-3-0:amd64 3.6.0-0ubuntu3.2
I see this with evolution and overlay scrollbars disabled.
I disabled overlay scrollbars with:
$gsettings set com.canonical. desktop. interface scrollbar-mode normal
(evolution:13228): Gtk-WARNING **: GtkScrolledWindow 0x7f8fa3f4faa0 is mapped but visible child GtkScrollbar 0x7f8fa409c540 is not mapped
My versions from current Ubuntu 12.10 (with proposed, updates sources enabled)
ii evolution 3.6.2-0ubuntu0.1
ii libgtk-3-0:amd64 3.6.0-0ubuntu3.2