Possible to show sway's mode message as multi-line?

[rieje]

Is it possible to show sway's mode message as multi-line? Currently, it shows only as a long line taking up a lot of space on the status bar (not enough room for the message). For example, I use the mode message to display available keys/actions in that mode:

set $screenshot screenshot: (a) active window (o) all visible output (s) current output (r) region (w) window (p) pixel...
mode "$screenshot" {

I would prefer to show this as multi-line for easier readability. If not, is there a way to get the effect of that, e.g. launch the mode, display this multi-line key/action legend message, and when exiting the mode, hide that message since I only need it when the mode is active?