When a layer surface is destroyed focus should be returned to the last client. Luckily if there are multiple overlays the previous overlay still gets focused.
FC37JD7W53YYYY7ZFXCYZ3F62BRT5YACMMVNCLAFFIQSCT5H22QAC
EDMIP6NWRBPL24VODBTEDFMVJXWTSO7W7HKYTMXZNQKWNVLANJQQC
GX2PWWI3Y7BOEOUIXW5NS4SYX4SXRWUC4TZ4RALA3AVCPX23CUEAC
VCNLR5X75OAXVKPZQHF5RUZ7BONBUC6RPGO2NZEUD3FZ7TEVL66AC
7B74AT3BXYB7PVW4F6SGQNPMHOU5TEV5TZ54CG6VSQI46XSEKWXQC
wlr_seat_keyboard_notify_clear_focus(seat); /* XXX recheck keyboard focus */
wlr_seat_keyboard_notify_clear_focus(seat);
/* XXX recheck keyboard focus */
focusclient(NULL, selclient(), 1);