diff --git a/libs/ardour/ardour/session_event.h b/libs/ardour/ardour/session_event.h
index 510dac01db..3f7fc6c092 100644
--- a/libs/ardour/ardour/session_event.h
+++ b/libs/ardour/ardour/session_event.h
@@ -141,7 +141,7 @@ public:
 	void* operator new (size_t);
 	void  operator delete (void *ptr, size_t /*size*/);
 
-	static const framepos_t Immediate = 0;
+	static const framepos_t Immediate = -1;
 
 	static void create_per_thread_pool (const std::string& n, uint32_t nitems);
 	static void init_event_pool ();
diff --git a/libs/ardour/session_events.cc b/libs/ardour/session_events.cc
index 03afd54440..e529c1b94a 100644
--- a/libs/ardour/session_events.cc
+++ b/libs/ardour/session_events.cc
@@ -115,7 +115,7 @@ SessionEventManager::replace_event (SessionEvent::Type type, framepos_t frame, f
 void
 SessionEventManager::clear_events (SessionEvent::Type type)
 {
-	SessionEvent* ev = new SessionEvent (type, SessionEvent::Clear, 0, 0, 0);
+	SessionEvent* ev = new SessionEvent (type, SessionEvent::Clear, SessionEvent::Immediate, 0, 0);
 	queue_event (ev);
 }
 
@@ -168,7 +168,7 @@ SessionEventManager::merge_event (SessionEvent* ev)
 
 	/* try to handle immediate events right here */
 
-	if (ev->action_frame == 0) {
+	if (ev->action_frame == SessionEvent::Immediate) {
 		process_event (ev);
 		return;
 	}