Constant FLOAT_CARD_ROOM 

pub const FLOAT_CARD_ROOM: f64 = _; // 8f64

The room a float’s card keeps inside the desk on every side: the band of the card’s own ground round the window and the focus ring drawn outside that. A float placed to the desk’s edge stands this far in, and the strip makes room for it beside a neighbour, so the whole card it draws — ring and band — shows on the desk instead of under the bar above it, past the display, or over the window it opened beside.