diff --git a/gtk2_ardour/pianoroll_automation_line.h b/gtk2_ardour/pianoroll_automation_line.h
index d0f8518393..d30da57b7a 100644
--- a/gtk2_ardour/pianoroll_automation_line.h
+++ b/gtk2_ardour/pianoroll_automation_line.h
@@ -16,8 +16,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#ifndef __gtk2_ardour_pianoroll_automation_line_h__
-#define __gtk2_ardour_pianoroll_automation_line_h__
+#pragma once
 
 #include "automation_line.h"
 
@@ -34,5 +33,3 @@ class PianorollAutomationLine : public AutomationLine
 	bool base_event_handler (GdkEvent*);
 	bool event_handler (GdkEvent*);
 };
-
-#endif /* __gtk2_ardour_midi_cue_automation_line_base_h__ */
diff --git a/gtk2_ardour/pianoroll_background.h b/gtk2_ardour/pianoroll_background.h
index bb8e0a2388..2da2ecdec3 100644
--- a/gtk2_ardour/pianoroll_background.h
+++ b/gtk2_ardour/pianoroll_background.h
@@ -20,8 +20,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#ifndef __gtk2_ardour_pianoroll_background_h__
-#define __gtk2_ardour_pianoroll_background_h__
+#pragma once
 
 #include <cstdint>
 
@@ -57,6 +56,3 @@ class CueMidiBackground : public MidiViewBackground
 
 	void apply_note_range_to_children();
 };
-
-
-#endif /* __gtk2_ardour_pianoroll_background_h__ */
diff --git a/gtk2_ardour/pianoroll_velocity.h b/gtk2_ardour/pianoroll_velocity.h
index d965e76be9..5e33afb080 100644
--- a/gtk2_ardour/pianoroll_velocity.h
+++ b/gtk2_ardour/pianoroll_velocity.h
@@ -16,8 +16,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#ifndef __gtk2_ardour_pianoroll_velocity_h__
-#define __gtk2_ardour_pianoroll_velocity_h__
+#pragma once
 
 #include "ghost_event.h"
 #include "velocity_display.h"
@@ -39,5 +38,3 @@ class PianorollVelocityDisplay : public VelocityDisplay
 	bool base_event (GdkEvent*);
 	bool lollevent (GdkEvent*, GhostEvent*);
 };
-
-#endif /* __gtk2_ardour_pianoroll_velocity_h__ */