Fix layer sufaces holding focus after unmap

src/layer_surface.zig

@@ -117,7 +117,17 @@ pub const LayerSurface = struct {
             }
         }
 
+        // This gives exclusive focus to a keyboard interactive top or overlay layer
+        // surface if there is one.
         layer_surface.output.arrangeLayers();
+
+        // Ensure that focus is given to the appropriate view if there is no
+        // other top/overlay layer surface to grab focus.
+        it = layer_surface.output.root.server.input_manager.seats.first;
+        while (it) |node| : (it = node.next) {
+            const seat = &node.data;
+            seat.focus(null);
+        }
     }
 
     fn handleCommit(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {

src/output.zig

@@ -259,7 +259,10 @@ pub const Output = struct {
             var it = self.layers[layer].last;
             while (it) |node| : (it = node.prev) {
                 const layer_surface = &node.data;
-                if (layer_surface.wlr_layer_surface.current.keyboard_interactive) {
+                // Only mapped surfaces may gain focus
+                if (layer_surface.mapped and
+                    layer_surface.wlr_layer_surface.current.keyboard_interactive)
+                {
                     break :outer layer_surface;
                 }
             }

src/seat.zig

@@ -161,7 +161,8 @@ pub const Seat = struct {
                 std.debug.assert(self.focused_layer == null);
                 current_focus.setActivated(false);
                 self.focused_view = null;
-            } else if (self.focused_layer) |current_focus| {
+            }
+            if (self.focused_layer) |current_focus| {
                 std.debug.assert(self.focused_view == null);
                 self.focused_layer = null;
             }