diff --git a/src/apps/activitymonitor/ActivityView.cpp b/src/apps/activitymonitor/ActivityView.cpp
index b28d1c30ed..fc24069f5e 100644
--- a/src/apps/activitymonitor/ActivityView.cpp
+++ b/src/apps/activitymonitor/ActivityView.cpp
@@ -644,6 +644,7 @@ ActivityView::MouseDown(BPoint where)
 	BPopUpMenu *menu = new BPopUpMenu(B_EMPTY_STRING, false, false);
 	menu->SetFont(be_plain_font);
 
+	BMenu* additionalMenu = new BMenu("Additional Items");
 	SystemInfo info;
 	BMenuItem* item;
 
@@ -660,9 +661,13 @@ ActivityView::MouseDown(BPoint where)
 		if (FindDataSource(source))
 			item->SetMarked(true);
 
-		menu->AddItem(item);
+		if (source->Primary())
+			menu->AddItem(item);
+		else
+			additionalMenu->AddItem(item);
 	}
 
+	menu->AddItem(new BMenuItem(additionalMenu));
 	menu->AddSeparatorItem();
 	menu->AddItem(new BMenuItem(fShowLegend ? "Hide Legend" : "Show Legend",
 		new BMessage(kMsgToggleLegend)));
diff --git a/src/apps/activitymonitor/DataSource.cpp b/src/apps/activitymonitor/DataSource.cpp
index cc9cd3f3be..e5963fd1d3 100644
--- a/src/apps/activitymonitor/DataSource.cpp
+++ b/src/apps/activitymonitor/DataSource.cpp
@@ -196,6 +196,13 @@ DataSource::MultiCPUOnly() const
 }
 
 
+bool
+DataSource::Primary() const
+{
+	return false;
+}
+
+
 /*static*/ int32
 DataSource::CountSources()
 {
@@ -308,6 +315,13 @@ UsedMemoryDataSource::Label() const
 }
 
 
+bool
+UsedMemoryDataSource::Primary() const
+{
+	return true;
+}
+
+
 //	#pragma mark -
 
 
@@ -343,6 +357,13 @@ CachedMemoryDataSource::Label() const
 }
 
 
+bool
+CachedMemoryDataSource::Primary() const
+{
+	return true;
+}
+
+
 //	#pragma mark -
 
 
@@ -682,6 +703,13 @@ CPUUsageDataSource::PerCPU() const
 }
 
 
+bool
+CPUUsageDataSource::Primary() const
+{
+	return true;
+}
+
+
 void
 CPUUsageDataSource::_SetCPU(int32 cpu)
 {
@@ -798,6 +826,13 @@ CPUCombinedUsageDataSource::MultiCPUOnly() const
 }
 
 
+bool
+CPUCombinedUsageDataSource::Primary() const
+{
+	return true;
+}
+
+
 //	#pragma mark -
 
 
@@ -885,6 +920,13 @@ NetworkUsageDataSource::AdaptiveScale() const
 }
 
 
+bool
+NetworkUsageDataSource::Primary() const
+{
+	return true;
+}
+
+
 //	#pragma mark -
 
 
diff --git a/src/apps/activitymonitor/DataSource.h b/src/apps/activitymonitor/DataSource.h
index 5e5f1c26e0..f0229b47f8 100644
--- a/src/apps/activitymonitor/DataSource.h
+++ b/src/apps/activitymonitor/DataSource.h
@@ -41,6 +41,7 @@ public:
 	virtual int32		CPU() const;
 	virtual bool		PerCPU() const;
 	virtual bool		MultiCPUOnly() const;
+	virtual bool		Primary() const;
 
 	static int32		CountSources();
 	static const DataSource* SourceAt(int32 index);
@@ -74,6 +75,7 @@ public:
 
 	virtual	int64		NextValue(SystemInfo& info);
 	virtual const char*	Label() const;
+	virtual bool		Primary() const;
 };
 
 
@@ -86,6 +88,7 @@ public:
 
 	virtual	int64		NextValue(SystemInfo& info);
 	virtual const char*	Label() const;
+	virtual bool		Primary() const;
 };
 
 
@@ -171,6 +174,7 @@ public:
 
 	virtual int32		CPU() const;
 	virtual bool		PerCPU() const;
+	virtual bool		Primary() const;
 
 private:
 			void		_SetCPU(int32 cpu);
@@ -198,6 +202,7 @@ public:
 	virtual const char*	Label() const;
 
 	virtual bool		MultiCPUOnly() const;
+	virtual bool		Primary() const;
 
 private:
 	bigtime_t			fPreviousActive;
@@ -220,6 +225,7 @@ public:
 	virtual const char*	Name() const;
 	virtual const char*	Label() const;
 	virtual bool		AdaptiveScale() const;
+	virtual bool		Primary() const;
 
 private:
 	bool				fIn;