diff --git a/src/ass_file.cpp b/src/ass_file.cpp
index 75c44c8f9..bd06c562e 100644
--- a/src/ass_file.cpp
+++ b/src/ass_file.cpp
@@ -177,11 +177,7 @@ int AssFile::Commit(wxString const& desc, int type, int amend_id, AssDialogue *s
 
 	PushState({desc, &amend_id, single_line});
 
-	std::set<const AssDialogue*> changed_lines;
-	if (single_line)
-		changed_lines.insert(single_line);
-
-	AnnounceCommit(type, changed_lines);
+	AnnounceCommit(type, single_line);
 
 	return amend_id;
 }
diff --git a/src/ass_file.h b/src/ass_file.h
index f291c2ea3..db848cd1e 100644
--- a/src/ass_file.h
+++ b/src/ass_file.h
@@ -80,7 +80,7 @@ struct ProjectProperties {
 
 class AssFile {
 	/// A set of changes has been committed to the file (AssFile::COMMITType)
-	agi::signal::Signal<int, std::set<const AssDialogue*> const&> AnnounceCommit;
+	agi::signal::Signal<int, const AssDialogue*> AnnounceCommit;
 	agi::signal::Signal<AssFileCommit> PushState;
 public:
 	/// The lines in the file
diff --git a/src/async_video_provider.cpp b/src/async_video_provider.cpp
index 72a6d8bfb..33dbe4bca 100644
--- a/src/async_video_provider.cpp
+++ b/src/async_video_provider.cpp
@@ -115,24 +115,19 @@ void AsyncVideoProvider::LoadSubtitles(const AssFile *new_subs) throw() {
 	});
 }
 
-void AsyncVideoProvider::UpdateSubtitles(const AssFile *new_subs, std::set<const AssDialogue*> const& changes) throw() {
+void AsyncVideoProvider::UpdateSubtitles(const AssFile *new_subs, const AssDialogue *changed) throw() {
 	uint_fast32_t req_version = ++version;
 
-	// Copy just the lines which were changed, then replace the lines at the
-	// same indices in the worker's copy of the file with the new entries
-	std::vector<AssDialogue *> changed;
-	for (auto d : changes)
-		changed.push_back(new AssDialogue(*d));
-
+	// Copy just the line which were changed, then replace the line at the
+	// same index in the worker's copy of the file with the new entry
+	auto copy = new AssDialogue(*changed);
 	worker->Async([=]{
 		int i = 0;
 		auto it = subs->Events.begin();
-		for (auto& update : changed) {
-			std::advance(it, update->Row - i);
-			i = update->Row;
-			subs->Events.insert(it, *update);
-			delete &*it--;
-		}
+		std::advance(it, copy->Row - i);
+		i = copy->Row;
+		subs->Events.insert(it, *copy);
+		delete &*it--;
 
 		single_frame = NEW_SUBS_FILE;
 		ProcAsync(req_version, true);
diff --git a/src/async_video_provider.h b/src/async_video_provider.h
index 139f7bc2a..ce5c83dbc 100644
--- a/src/async_video_provider.h
+++ b/src/async_video_provider.h
@@ -92,7 +92,7 @@ public:
 	///
 	/// This function only supports changes to existing lines, and not
 	/// insertions or deletions.
-	void UpdateSubtitles(const AssFile *subs, std::set<const AssDialogue *> const& changes) throw();
+	void UpdateSubtitles(const AssFile *subs, const AssDialogue *changes) throw();
 
 	/// @brief Queue a request for a frame
 	/// @brief frame Frame number
diff --git a/src/audio_karaoke.cpp b/src/audio_karaoke.cpp
index 60dd4c390..6d3d16fa9 100644
--- a/src/audio_karaoke.cpp
+++ b/src/audio_karaoke.cpp
@@ -113,8 +113,8 @@ void AudioKaraoke::OnActiveLineChanged(AssDialogue *new_line) {
 	}
 }
 
-void AudioKaraoke::OnFileChanged(int type, std::set<const AssDialogue *> const& changed) {
-	if (enabled && (type & AssFile::COMMIT_DIAG_FULL) && (changed.empty() || changed.count(active_line))) {
+void AudioKaraoke::OnFileChanged(int type, const AssDialogue *changed) {
+	if (enabled && (type & AssFile::COMMIT_DIAG_FULL) && (!changed || changed == active_line)) {
 		LoadFromLine();
 		split_area->Refresh(false);
 	}
diff --git a/src/audio_karaoke.h b/src/audio_karaoke.h
index e798bfc2b..2d14207d0 100644
--- a/src/audio_karaoke.h
+++ b/src/audio_karaoke.h
@@ -137,7 +137,7 @@ class AudioKaraoke final : public wxWindow {
 	void OnActiveLineChanged(AssDialogue *new_line);
 	void OnContextMenu(wxContextMenuEvent&);
 	void OnEnableButton(wxCommandEvent &evt);
-	void OnFileChanged(int type, std::set<const AssDialogue *> const& changed);
+	void OnFileChanged(int type, const AssDialogue *changed);
 	void OnMouse(wxMouseEvent &event);
 	void OnPaint(wxPaintEvent &event);
 	void OnSize(wxSizeEvent &event);
diff --git a/src/video_controller.cpp b/src/video_controller.cpp
index afe3b0865..065247797 100644
--- a/src/video_controller.cpp
+++ b/src/video_controller.cpp
@@ -65,7 +65,7 @@ void VideoController::OnNewVideoProvider(AsyncVideoProvider *new_provider) {
 	color_matrix = provider ? provider->GetColorSpace() : "";
 }
 
-void VideoController::OnSubtitlesCommit(int type, std::set<const AssDialogue *> const& changed) {
+void VideoController::OnSubtitlesCommit(int type, const AssDialogue *changed) {
 	if (!provider) return;
 
 	if ((type & AssFile::COMMIT_SCRIPTINFO) || type == AssFile::COMMIT_NEW) {
@@ -76,10 +76,10 @@ void VideoController::OnSubtitlesCommit(int type, std::set<const AssDialogue *>
 		}
 	}
 
-	if (changed.empty())
+	if (!changed)
 		provider->LoadSubtitles(context->ass.get());
 	else
-		provider->UpdateSubtitles(context->ass.get(), changed);
+		provider->UpdateSubtitles(context->ass.get(), {changed});
 }
 
 void VideoController::OnActiveLineChanged(AssDialogue *line) {
diff --git a/src/video_controller.h b/src/video_controller.h
index 27b5a4342..c15c5c8f1 100644
--- a/src/video_controller.h
+++ b/src/video_controller.h
@@ -104,7 +104,7 @@ class VideoController final : public wxEvtHandler {
 	void OnVideoError(VideoProviderErrorEvent const& err);
 	void OnSubtitlesError(SubtitlesProviderErrorEvent const& err);
 
-	void OnSubtitlesCommit(int type, std::set<const AssDialogue *> const& changed);
+	void OnSubtitlesCommit(int type, const AssDialogue *changed);
 	void OnNewVideoProvider(AsyncVideoProvider *provider);
 	void OnActiveLineChanged(AssDialogue *line);