what does it mean when the colours get bigger as i mouse over them? is something else meant to happen? i guess that should mean they are clickable, or that so

what does it mean when the colours get bigger as i mouse over them? is something else meant to happen? i guess that should mean they are clickable, or that something else is changing, but i don't see anything else change and nothing happens when i click. is something broken (chrome latest stable, linux)? [edit: and if not, please don't do that.]