diff --git a/.zshrc b/.zshrc
index b9f0048..d65bb8b 100644
--- a/.zshrc
+++ b/.zshrc
@@ -34,6 +34,9 @@ if [[ "$OSTYPE" =~ ^linux.*$ ]]; then
 
     if [[ -n $WAYLAND_DISPLAY ]]; then
         export MOZ_ENABLE_WAYLAND=1
+        # 2021-06-22: fix "Firefox is already running" message
+        # See: https://mastransky.wordpress.com/2020/03/16/wayland-x11-how-to-run-firefox-in-mixed-environment/
+        export MOZ_DBUS_REMOTE=1
         export KITTY_ENABLE_WAYLAND=1
         export QT_QPA_PLATFORM=wayland-egl
         export CLUTTER_BACKEND=wayland