diff --git a/aegisub/src/subs_edit_box.cpp b/aegisub/src/subs_edit_box.cpp
index 279c0e982..20f4d1f7b 100644
--- a/aegisub/src/subs_edit_box.cpp
+++ b/aegisub/src/subs_edit_box.cpp
@@ -329,7 +329,7 @@ SubsEditBox::SubsEditBox(wxWindow *parent, agi::Context *context)
 	OnSize(evt);
 
 	c->subsGrid->AddSelectionListener(this);
-	c->ass->AddCommitListener(&SubsEditBox::Update, this);
+	file_changed_slot = c->ass->AddCommitListener(&SubsEditBox::Update, this);
 	context->videoController->AddTimecodesListener(&SubsEditBox::UpdateFrameTiming, this);
 }
 SubsEditBox::~SubsEditBox() {
@@ -465,12 +465,14 @@ void SubsEditBox::NextLine() {
 
 void SubsEditBox::OnChange(wxStyledTextEvent &event) {
 	if (line && TextEdit->GetText() != line->Text) {
+		file_changed_slot.Block();
 		if (event.GetModificationType() & wxSTC_MOD_INSERTTEXT) {
 			CommitText(_("insert text"));
 		}
 		else {
 			CommitText(_("delete text"));
 		}
+		file_changed_slot.Unblock();
 	}
 }
 
diff --git a/aegisub/src/subs_edit_box.h b/aegisub/src/subs_edit_box.h
index 46fac4ae9..3830a9f4a 100644
--- a/aegisub/src/subs_edit_box.h
+++ b/aegisub/src/subs_edit_box.h
@@ -40,6 +40,8 @@
 #include <wx/panel.h>
 #endif
 
+#include <libaegisub/signal.h>
+
 #include "selection_controller.h"
 
 namespace agi { struct Context; }
@@ -85,6 +87,8 @@ class SubsEditBox : public wxPanel, protected SelectionListener<AssDialogue> {
 
 	agi::Context *c;
 
+	agi::signal::Connection file_changed_slot;
+
 	// Box controls
 	wxCheckBox *CommentBox;
 	wxComboBox *StyleBox;