Lines to cards you have scrolled past

Open a Blocked, Blocking or Relates to panel and thin lines join the card to each linked card. That works while both cards are on screen. Each column scrolls on its own, though, and a linked card scrolled above or below its column's visible list still had a position, often hundreds of pixels off the board. The line aimed at that point, left the board wherever that bearing crossed its edge, and the label ended up between two columns, pointing at nothing you could find.

Now the line knows which column the card is in.

• It stops at the column. When the linked card is scrolled out of view, the line ends at the top or bottom edge of that column's list, on the side nearest the card you started from, with an arrowhead pointing straight up or straight down. The arrowhead means "scroll this column this way", not which issue blocks which.
• The label is a button. It reads ↑ #210 or ↓ #210. Click it and the column glides to the card over most of a second, eased in and out, then flashes it, so you can follow where you went. If the column alone can't bring the card into view, the page scrolls the rest of the way. Focus stays where it was. If your motion setting is off, or your system asks for reduced motion and you haven't overridden it, the column jumps straight there instead.
• The line waits for you. A line that ends at a column edge stays up for a moment after the pointer leaves the chip, and for as long as the pointer is on the label, so there is time to reach it. A line to a card already in view clears as before.
• Arrival. Once the card is in view, the line is redrawn to the card itself and stays for a moment, so both ends of the link are on screen together before it fades.

Cards off the edge of the whole board, and cards in a collapsed column, behave as before: an arrowhead at the board's edge, or one line to the column's strip.