diff --git a/aegisub/src/base_grid.cpp b/aegisub/src/base_grid.cpp
index bebad4b8d..0b48e9e36 100644
--- a/aegisub/src/base_grid.cpp
+++ b/aegisub/src/base_grid.cpp
@@ -80,7 +80,6 @@ BaseGrid::BaseGrid(wxWindow* parent, wxWindowID id, const wxPoint& pos, const wx
 	holding = false;
 	byFrame = false;
 	lineHeight = 1; // non-zero to avoid div by 0
-	selChangeSub = NULL;
 
 	// Set scrollbar
 	scrollBar = new wxScrollBar(this,GRID_SCROLLBAR,wxDefaultPosition,wxDefaultSize,wxSB_VERTICAL);
@@ -142,6 +141,10 @@ void BaseGrid::UpdateStyle() {
 /// @brief Clears grid 
 ///
 void BaseGrid::Clear () {
+	Selection lines_removed;
+	GetSelectedSet(lines_removed);
+	AnnounceSelectedSetChanged(Selection(), lines_removed);
+
 	diagMap.clear();
 	diagPtrMap.clear();
 	selMap.clear();
@@ -209,7 +212,11 @@ void BaseGrid::MakeCellVisible(int row, int col,bool center) {
 ///
 void BaseGrid::SelectRow(int row, bool addToSelected, bool select) {
 	if (row < 0 || (size_t)row >= selMap.size()) return;
-	if (!addToSelected) ClearSelection();
+
+	if (!addToSelected) {
+		// Sends change notifications for itself
+		ClearSelection();
+	}
 
 	if (select != !!selMap[row]) {
 		selMap[row] = select;
@@ -224,7 +231,14 @@ void BaseGrid::SelectRow(int row, bool addToSelected, bool select) {
 			RefreshRect(wxRect(0,(row+1-yPos)*lineHeight,w,lineHeight),false);
 		}
 
-		if (selChangeSub) selChangeSub->OnSelectionChange(!addToSelected, row, select);
+		Selection lines_added;
+		Selection lines_removed;
+		if (select)
+			lines_added.insert(diagPtrMap[row]);
+		else
+			lines_removed.insert(diagPtrMap[row]);
+
+		AnnounceSelectedSetChanged(lines_added, lines_removed);
 	}
 }
 
@@ -233,6 +247,9 @@ void BaseGrid::SelectRow(int row, bool addToSelected, bool select) {
 /// @brief Selects visible lines 
 ///
 void BaseGrid::SelectVisible() {
+	Selection lines_removed;
+	GetSelectedSet(lines_removed);
+
 	int rows = GetRows();
 	bool selectedOne = false;
 	for (int i=0;i<rows;i++) {
@@ -247,6 +264,11 @@ void BaseGrid::SelectVisible() {
 			}
 		}
 	}
+
+	Selection lines_added;
+	GetSelectedSet(lines_added);
+
+	AnnounceSelectedSetChanged(lines_added, lines_removed);
 }
 
 
@@ -254,11 +276,16 @@ void BaseGrid::SelectVisible() {
 /// @brief Unselects all cells 
 ///
 void BaseGrid::ClearSelection() {
+	Selection lines_removed;
+	GetSelectedSet(lines_removed);
+
 	int rows = selMap.size();
 	for (int i=0;i<rows;i++) {
 		selMap[i] = false;
 	}
 	Refresh(false);
+
+	AnnounceSelectedSetChanged(Selection(), lines_removed);
 }
 
 
@@ -309,8 +336,8 @@ int BaseGrid::GetLastSelRow() const {
 
 
 /// @brief Gets all selected rows 
-/// @param[out] cont 
-/// @return 
+/// @param[out] cont Is the selection contiguous, i.e. free from holes
+/// @return Array with indices of selected lines
 ///
 wxArrayInt BaseGrid::GetSelection(bool *cont) const {
 	// Prepare
@@ -1180,3 +1207,16 @@ wxArrayInt BaseGrid::GetRangeArray(int n1,int n2) const {
 }
 
 
+
+// SelectionController
+
+
+void BaseGrid::GetSelectedSet(Selection &selection) const {
+	for (size_t i = 0; i < selMap.size(); ++i) {
+		if (selMap[i] != 0) {
+			selection.insert(GetDialogue((int)i));
+		}
+	}
+}
+
+
diff --git a/aegisub/src/base_grid.h b/aegisub/src/base_grid.h
index 03dd22bb4..3b7f149ed 100644
--- a/aegisub/src/base_grid.h
+++ b/aegisub/src/base_grid.h
@@ -60,11 +60,9 @@ class FrameMain;
 /// DOCME
 typedef std::list<AssEntry*>::iterator entryIter;
 
-class SelectionChangeSubscriber {
-public:
-	virtual void OnSelectionChange(bool clear, int row, bool selected) = 0;
-};
 
+typedef SelectionController<AssDialogue> SubtitleSelectionController;
+typedef SelectionListener<AssDialogue> SubtitleSelectionListener;
 
 
 /// DOCME
@@ -72,7 +70,7 @@ public:
 /// @brief DOCME
 ///
 /// DOCME
-class BaseGrid : public wxWindow, public BaseSelectionController<AssEntry> {
+class BaseGrid : public wxWindow, public BaseSelectionController<AssDialogue> {
 private:
 
 	/// DOCME
@@ -99,8 +97,6 @@ private:
 	/// DOCME
 	wxBitmap *bmp;
 
-	SelectionChangeSubscriber* selChangeSub;
-
 	void OnPaint(wxPaintEvent &event);
 	void OnSize(wxSizeEvent &event);
 	void OnScroll(wxScrollEvent &event);
@@ -133,10 +129,10 @@ protected:
 
 public:
 	// SelectionController implementation
-	virtual void SetActiveLine(AssEntry *new_line) { }
-	virtual AssEntry * GetActiveLine() const { return 0; }
+	virtual void SetActiveLine(AssDialogue *new_line) { }
+	virtual AssDialogue * GetActiveLine() const { return 0; }
 	virtual void SetSelectedSet(const Selection &new_selection) { }
-	virtual void GetSelectedSet(Selection &selection) const { }
+	virtual void GetSelectedSet(Selection &selection) const;
 	virtual void NextLine() { }
 	virtual void PrevLine() { }
 
@@ -181,10 +177,6 @@ public:
 
 	AssDialogue *GetDialogue(int n) const;
 
-	void RegisterSelectionChange(SelectionChangeSubscriber* sel) {
-		selChangeSub = sel;
-	}
-
 	BaseGrid(wxWindow* parent, wxWindowID id, const wxPoint& pos = wxDefaultPosition, const wxSize& size = wxDefaultSize, long style = wxWANTS_CHARS, const wxString& name = wxPanelNameStr);
 	~BaseGrid();
 
diff --git a/aegisub/src/selection_controller.h b/aegisub/src/selection_controller.h
index 39ac82987..dffdd18ce 100644
--- a/aegisub/src/selection_controller.h
+++ b/aegisub/src/selection_controller.h
@@ -47,13 +47,21 @@ public:
 	/// Virtual destructor for safety
 	virtual ~SelectionListener() { }
 
-	/// @brief Called when the active subtitle line changes
-	/// @param new_line The subtitle line that is now the active line
+	/// @brief Called when the active line changes
+	/// @param new_line The line that is now the active line
+	///
+	/// In case new_line is 0, the active line was changed to none.
 	virtual void OnActiveLineChanged(ItemDataType *new_line) = 0;
 
 	/// @brief Called when the selected set changes
-	/// @param new_selection The subtitle line set that is now the selected set
-	virtual void OnSelectedSetChanged(const Selection &new_selection) = 0;
+	/// @param lines_added   Lines added to the selection
+	/// @param lines_removed Lines removed from the selection
+	///
+	/// Conceptually, removal happens before addition, for the purpose of this change notification.
+	///
+	/// In case the two sets overlap, the intersection are lines that were previously selected
+	/// and remain selected.
+	virtual void OnSelectedSetChanged(const Selection &lines_added, const Selection &lines_removed) = 0;
 };
 
 
@@ -165,11 +173,11 @@ protected:
 	}
 
 	/// Call OnSelectedSetChangedon all listeners
-	void AnnounceSelectedSetChanged(const Selection &new_selection)
+	void AnnounceSelectedSetChanged(const Selection &lines_added, const Selection &lines_removed)
 	{
 		for (SelectionListenerSet::iterator listener = listeners.begin(); listener != listeners.end(); ++listener)
 		{
-			(*listener)->OnSelectedSetChanged(new_selection);
+			(*listener)->OnSelectedSetChanged(lines_added, lines_removed);
 		}
 	}
 
diff --git a/aegisub/src/visual_tool.cpp b/aegisub/src/visual_tool.cpp
index 7c807ce1b..2c51ebbaa 100644
--- a/aegisub/src/visual_tool.cpp
+++ b/aegisub/src/visual_tool.cpp
@@ -92,7 +92,7 @@ VisualTool<FeatureType>::VisualTool(VideoDisplay *parent, VideoState const& vide
 {
 	if (VideoContext::Get()->IsLoaded()) {
 		frame_n = VideoContext::Get()->GetFrameN();
-		VideoContext::Get()->grid->RegisterSelectionChange(this);
+		VideoContext::Get()->grid->AddSelectionListener(this);
 	}
 
 	PopulateFeatureList();
@@ -100,7 +100,7 @@ VisualTool<FeatureType>::VisualTool(VideoDisplay *parent, VideoState const& vide
 
 template<class FeatureType>
 VisualTool<FeatureType>::~VisualTool() {
-	VideoContext::Get()->grid->RegisterSelectionChange(NULL);
+	VideoContext::Get()->grid->RemoveSelectionListener(this);
 }
 
 template<class FeatureType>
diff --git a/aegisub/src/visual_tool.h b/aegisub/src/visual_tool.h
index 4684c9fcf..5a783324b 100644
--- a/aegisub/src/visual_tool.h
+++ b/aegisub/src/visual_tool.h
@@ -79,7 +79,7 @@ public:
 /// @brief DOCME
 /// DOCME
 template<class FeatureType>
-class VisualTool : public IVisualTool, public SelectionChangeSubscriber {
+class VisualTool : public IVisualTool, protected SubtitleSelectionListener {
 private:
 	agi::OptionValue* realtime; /// Realtime updating option
 	int dragStartX; /// Starting x coordinate of the current drag, if any
@@ -187,6 +187,12 @@ protected:
 	typedef typename std::vector<FeatureType>::iterator feature_iterator;
 	typedef typename std::vector<FeatureType>::const_iterator feature_const_iterator;
 
+protected:
+	// SubtitleSelectionListener implementation
+	// (overridden by deriving classes too)
+	virtual void OnActiveLineChanged(AssDialogue *new_line) { }
+	virtual void OnSelectedSetChanged(const Selection &lines_added, const Selection &lines_removed) { }
+
 public:
 	/// @brief Handler for all mouse events
 	/// @param event Shockingly enough, the mouse event
@@ -202,9 +208,6 @@ public:
 	/// @brief Called by stuff when there's stuff
 	void Refresh();
 
-	/// Called by the grid when the selection changes
-	virtual void OnSelectionChange(bool, int, bool) { }
-
 	/// @brief Constructor
 	/// @param parent The VideoDisplay to use for coordinate conversion
 	/// @param video Video and mouse information passing blob
diff --git a/aegisub/src/visual_tool_drag.cpp b/aegisub/src/visual_tool_drag.cpp
index 16c8356c6..c66eff395 100644
--- a/aegisub/src/visual_tool_drag.cpp
+++ b/aegisub/src/visual_tool_drag.cpp
@@ -121,27 +121,24 @@ void VisualToolDrag::DoRefresh() {
 	UpdateToggleButtons();
 }
 
-void VisualToolDrag::OnSelectionChange(bool clear, int row, bool selected) {
+void VisualToolDrag::OnSelectedSetChanged(const Selection &added, const Selection &removed) {
 	if (!externalChange) return;
 	externalChange = false;
-	if (clear) {
-		ClearSelection(false);
-	}
-	if (selected) {
-		for (size_t i = 0; i < features.size(); i++) {
-			if (features[i].lineN == row && features[i].type == DRAG_START) {
-				AddSelection(i);
-				break;
-			}
+
+	// Remove all deselected lines
+	for (size_t i = 0; i < features.size(); i++) {
+		if (removed.find(features[i].line) != removed.end()) {
+			RemoveSelection(i);
 		}
 	}
-	else {
-		for (size_t i = 0; i < features.size(); i++) {
-			if (features[i].lineN == row) {
-				RemoveSelection(i);
-			}
+
+	// And add all newly selected lines
+	for (size_t i = 0; i < features.size(); i++) {
+		if (added.find(features[i].line) != added.end() && features[i].type == DRAG_START) {
+			AddSelection(i);
 		}
 	}
+
 	externalChange = true;
 }
 
diff --git a/aegisub/src/visual_tool_drag.h b/aegisub/src/visual_tool_drag.h
index dde2e3289..f082a8705 100644
--- a/aegisub/src/visual_tool_drag.h
+++ b/aegisub/src/visual_tool_drag.h
@@ -82,11 +82,13 @@ private:
 	void UpdateToggleButtons();
 	void DoRefresh();
 
+protected:
+	// Overriding SubtitleSelectionListener inherited from base VisualTool<>
+	virtual void OnSelectedSetChanged(const Selection &lines_added, const Selection &lines_removed);
+
 public:
 	VisualToolDrag(VideoDisplay *parent, VideoState const& video, wxToolBar *toolbar);
 
-	void OnSelectionChange(bool clear, int row, bool selected);
-
 	void Draw();
 	bool Update();
 	void OnSubTool(wxCommandEvent &event);