Attaching screenshots demonstrating minimal height of layer list depending on Gtk+ theme settings (for scroll bars):
1) Default Ambiance theme (from Ubuntu's 'light-themes'), no scrollbar-overlay on OS X
Tweaked Ambiance theme mimicking a minimalistic scroll bar
2) Default Clearlooks theme (same file with 5 layers)
Attaching screenshots demonstrating minimal height of layer list depending on Gtk+ theme settings (for scroll bars):
1) Default Ambiance theme (from Ubuntu's 'light-themes'), no scrollbar-overlay on OS X
Tweaked Ambiance theme mimicking a minimalistic scroll bar
2) Default Clearlooks theme (same file with 5 layers)