diff --git a/gtk2_ardour/opts.cc b/gtk2_ardour/opts.cc
index 9e5cbc6f3f..4e03983f85 100644
--- a/gtk2_ardour/opts.cc
+++ b/gtk2_ardour/opts.cc
@@ -25,6 +25,10 @@
 #include "ardour/debug.h"
 #include "ardour/session.h"
 
+#ifndef NDEBUG // "-H"
+#include "processor_box.h"
+#endif
+
 #include "opts.h"
 
 #include "i18n.h"
@@ -84,7 +88,7 @@ print_help (const char *execname)
 int
 ARDOUR_COMMAND_LINE::parse_opts (int argc, char *argv[])
 {
-	const char *optstring = "abBc:C:dD:hk:E:m:N:nOp:PST:U:vV";
+	const char *optstring = "abBc:C:dD:hHk:E:m:N:nOp:PST:U:vV";
 	const char *execname = strrchr (argv[0], '/');
 
 	if (getenv ("ARDOUR_SAE")) {
@@ -143,6 +147,11 @@ ARDOUR_COMMAND_LINE::parse_opts (int argc, char *argv[])
 			print_help (execname);
 			exit (0);
 			break;
+		case 'H':
+#ifndef NDEBUG
+			ProcessorBox::show_all_processors = true;
+#endif
+			break;
 		case 'a':
 			check_announcements = false;
 			break;
diff --git a/gtk2_ardour/processor_box.cc b/gtk2_ardour/processor_box.cc
index c7df111322..509ffaaa47 100644
--- a/gtk2_ardour/processor_box.cc
+++ b/gtk2_ardour/processor_box.cc
@@ -82,6 +82,10 @@
 class AUPluginUI;
 #endif
 
+#ifndef NDEBUG
+bool ProcessorBox::show_all_processors = false;
+#endif
+
 using namespace std;
 using namespace ARDOUR;
 using namespace PBD;
@@ -1794,7 +1798,12 @@ ProcessorBox::help_count_visible_prefader_processors (boost::weak_ptr<Processor>
 {
 	boost::shared_ptr<Processor> processor (p.lock ());
 
-	if (processor && processor->display_to_user()) {
+	if (processor && ( processor->display_to_user()
+#ifndef NDEBUG
+	                    || show_all_processors
+#endif
+	                 )
+	   ) {
 
 		if (boost::dynamic_pointer_cast<Amp>(processor) && boost::dynamic_pointer_cast<Amp>(processor)->type() == X_("amp")) {
 			*amp_seen = true;
@@ -1811,7 +1820,12 @@ ProcessorBox::add_processor_to_display (boost::weak_ptr<Processor> p)
 {
 	boost::shared_ptr<Processor> processor (p.lock ());
 
-	if (!processor || !processor->display_to_user()) {
+	if (!processor || ( !processor->display_to_user()
+#ifndef NDEBUG
+	                    && !show_all_processors
+#endif
+	                  )
+	   ) {
 		return;
 	}
 
diff --git a/gtk2_ardour/processor_box.h b/gtk2_ardour/processor_box.h
index fcc70a6074..87ab0dee6c 100644
--- a/gtk2_ardour/processor_box.h
+++ b/gtk2_ardour/processor_box.h
@@ -310,6 +310,9 @@ class ProcessorBox : public Gtk::HBox, public PluginInterestedObject, public ARD
 	sigc::signal<void,boost::shared_ptr<ARDOUR::Processor> > ProcessorUnselected;
 
 	static void register_actions();
+#ifndef NDEBUG
+	static bool show_all_processors;
+#endif
 
   private: