diff --git a/libs/surfaces/osc/osc.cc b/libs/surfaces/osc/osc.cc
index 2bd3b198f8..9347486dd1 100644
--- a/libs/surfaces/osc/osc.cc
+++ b/libs/surfaces/osc/osc.cc
@@ -3181,20 +3181,6 @@ OSC::mixer_scene_state (lo_address addr, bool zero_it)
 	return 0;
 }
 
-// two structs to help with going to markers
-struct LocationMarker {
-	LocationMarker (const std::string& l, samplepos_t w)
-		: label (l), when (w) {}
-	std::string label;
-	samplepos_t  when;
-};
-
-struct LocationMarkerSort {
-	bool operator() (const LocationMarker& a, const LocationMarker& b) {
-		return (a.when < b.when);
-	}
-};
-
 int
 OSC::set_marker (const char* types, lo_arg **argv, int argc, lo_message msg)
 {
@@ -3202,6 +3188,7 @@ OSC::set_marker (const char* types, lo_arg **argv, int argc, lo_message msg)
 		PBD::warning << "Wrong number of parameters, one only." << endmsg;
 		return -1;
 	}
+
 	const Locations::LocationList& ll (session->locations ()->list ());
 	uint32_t marker = 0;
 
@@ -3237,15 +3224,15 @@ OSC::set_marker (const char* types, lo_arg **argv, int argc, lo_message msg)
 			return -1;
 			break;
 	}
-	std::vector<LocationMarker> lm;
+	std::vector<ArdourSurface::LocationMarker> lm;
 	// get Locations that are marks
 	for (Locations::LocationList::const_iterator l = ll.begin(); l != ll.end(); ++l) {
 		if ((*l)->is_mark ()) {
-			lm.push_back (LocationMarker((*l)->name(), (*l)->start_sample ()));
+			lm.push_back (ArdourSurface::LocationMarker((*l)->name(), (*l)->start_sample ()));
 		}
 	}
 	// sort them by position
-	LocationMarkerSort location_marker_sort;
+	ArdourSurface::LocationMarkerSort location_marker_sort;
 	std::sort (lm.begin(), lm.end(), location_marker_sort);
 	// go there
 	if (marker < lm.size()) {
diff --git a/libs/surfaces/osc/osc.h b/libs/surfaces/osc/osc.h
index 899a0fc62e..88749e32d8 100644
--- a/libs/surfaces/osc/osc.h
+++ b/libs/surfaces/osc/osc.h
@@ -51,7 +51,6 @@
 
 class OSCControllable;
 class OSCRouteObserver;
-class OSCGlobalObserver;
 class OSCSelectObserver;
 class OSCCueObserver;
 
@@ -68,6 +67,8 @@ class ZeroConf;
 
 namespace ArdourSurface {
 
+class OSCGlobalObserver;
+
 struct OSCUIRequest : public BaseUI::BaseRequestObject {
   public:
 	OSCUIRequest () {}
diff --git a/libs/surfaces/osc/osc_global_observer.h b/libs/surfaces/osc/osc_global_observer.h
index 4c08ae6e0c..2e205eb572 100644
--- a/libs/surfaces/osc/osc_global_observer.h
+++ b/libs/surfaces/osc/osc_global_observer.h
@@ -34,6 +34,22 @@
 #include "ardour/session.h"
 #include "ardour/types.h"
 
+namespace ArdourSurface {
+
+
+struct LocationMarker {
+	LocationMarker (const std::string& l, samplepos_t w)
+		: label (l), when (w) {}
+	std::string label;
+	samplepos_t  when;
+};
+
+struct LocationMarkerSort {
+	bool operator() (const LocationMarker& a, const LocationMarker& b) {
+		return (a.when < b.when);
+	}
+};
+
 class OSCGlobalObserver
 {
 
@@ -47,6 +63,8 @@ class OSCGlobalObserver
 	void jog_mode (uint32_t jogmode);
 
   private:
+	friend ArdourSurface::OSC;
+
 	ArdourSurface::OSC& _osc;
 
 	PBD::ScopedConnectionList strip_connections;
@@ -79,20 +97,8 @@ class OSCGlobalObserver
 	uint32_t last_click;
 	samplepos_t prev_mark;
 	samplepos_t next_mark;
-	struct LocationMarker {
-		LocationMarker (const std::string& l, samplepos_t w)
-			: label (l), when (w) {}
-		std::string label;
-		samplepos_t  when;
-	};
 	std::vector<LocationMarker> lm;
 
-	struct LocationMarkerSort {
-		bool operator() (const LocationMarker& a, const LocationMarker& b) {
-			return (a.when < b.when);
-		}
-	};
-
 	void update_mixer_scene_state();
 	void send_change_message (std::string path, std::shared_ptr<PBD::Controllable> controllable);
 	void send_gain_message (std::string path, std::shared_ptr<PBD::Controllable> controllable);
@@ -108,4 +114,6 @@ class OSCGlobalObserver
 	void group_changed (void);
 };
 
+} /* namespace */
+
 #endif /* __osc_oscglobalobserver_h__ */