diff --git a/Dockerfile b/Dockerfile
index b367fd7..e3cebfe 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -146,17 +146,8 @@
 # (2-2) Optional vulkan support
 # vulkan-utils includes vulkan-smoketest, benchmark software of vulkan API
 RUN apt-get update && apt-get install -y --no-install-recommends \
-        vulkan-utils && \
-    rm -rf /var/lib/apt/lists/*
-
-# for test
-RUN apt-get update && apt-get install -y --no-install-recommends \
-        firefox openbox menu && \
-    rm -rf /var/lib/apt/lists/*
-
-# sound driver and GTK library
-# If you want to use sounds on docker, try `pulseaudio --start`
-RUN apt-get update && apt-get install -y --no-install-recommends \
+      vulkan-utils \
+      firefox openbox menu \
       alsa pulseaudio libgtk2.0-0 && \
     rm -rf /var/lib/apt/lists/*