diff --git a/aegisub/src/subs_edit_ctrl.cpp b/aegisub/src/subs_edit_ctrl.cpp
index 9052c7a23..847d31d41 100644
--- a/aegisub/src/subs_edit_ctrl.cpp
+++ b/aegisub/src/subs_edit_ctrl.cpp
@@ -118,9 +118,9 @@ SubsTextEditCtrl::SubsTextEditCtrl(wxWindow* parent, wxSize wsize, long style, a
 		Bind(wxEVT_COMMAND_MENU_SELECTED, bind(&cmd::call, "edit/line/split/estimate", context), EDIT_MENU_SPLIT_ESTIMATE);
 	}
 
-	Bind(wxEVT_STC_STYLENEEDED, &SubsTextEditCtrl::UpdateCallTip, this);
-
+	Bind(wxEVT_STC_STYLENEEDED, std::bind(&SubsTextEditCtrl::UpdateStyle, this));
 	Bind(wxEVT_CONTEXT_MENU, &SubsTextEditCtrl::OnContextMenu, this);
+	Bind(wxEVT_IDLE, std::bind(&SubsTextEditCtrl::UpdateCallTip, this));
 
 	OPT_SUB("Subtitle/Edit Box/Font Face", &SubsTextEditCtrl::SetStyles, this);
 	OPT_SUB("Subtitle/Edit Box/Font Size", &SubsTextEditCtrl::SetStyles, this);
@@ -137,8 +137,7 @@ SubsTextEditCtrl::SubsTextEditCtrl(wxWindow* parent, wxSize wsize, long style, a
 	Subscribe("Karaoke Variable");
 
 	OPT_SUB("Subtitle/Highlight/Syntax", &SubsTextEditCtrl::UpdateStyle, this);
-	static wxStyledTextEvent evt;
-	OPT_SUB("App/Call Tips", &SubsTextEditCtrl::UpdateCallTip, this, std::ref(evt));
+	OPT_SUB("App/Call Tips", &SubsTextEditCtrl::UpdateCallTip, this);
 }
 
 SubsTextEditCtrl::~SubsTextEditCtrl() {
@@ -208,39 +207,43 @@ void SubsTextEditCtrl::SetStyles() {
 }
 
 void SubsTextEditCtrl::UpdateStyle() {
+	{
+		std::string text = GetTextRaw().data();
+		if (text == line_text) return;
+		line_text = move(text);
+	}
+	tokenized_line = agi::ass::TokenizeDialogueBody(line_text);
+
+	cursor_pos = -1;
+	UpdateCallTip();
+
 	StartStyling(0,255);
 
-	std::string text = GetTextRaw().data();
-
 	if (!OPT_GET("Subtitle/Highlight/Syntax")->GetBool()) {
-		SetStyling(text.size(), 0);
+		SetStyling(line_text.size(), 0);
 		return;
 	}
 
-	if (text.empty()) return;
+	if (line_text.empty()) return;
 
 	AssDialogue *diag = context ? context->selectionController->GetActiveLine() : 0;
 	bool template_line = diag && diag->Comment && diag->Effect.Lower().StartsWith("template");
 
-	auto tokens = agi::ass::TokenizeDialogueBody(text);
-	for (auto const& style_range : agi::ass::SyntaxHighlight(text, tokens, template_line, spellchecker.get()))
+	for (auto const& style_range : agi::ass::SyntaxHighlight(line_text, tokenized_line, template_line, spellchecker.get()))
 		SetStyling(style_range.length, style_range.type);
 }
 
-/// @brief Update call tip
-void SubsTextEditCtrl::UpdateCallTip(wxStyledTextEvent &) {
-	UpdateStyle();
-
+void SubsTextEditCtrl::UpdateCallTip() {
 	if (!OPT_GET("App/Call Tips")->GetBool()) return;
 
+	int pos = GetCurrentPos();
+	if (!pos == cursor_pos) return;
+	cursor_pos = pos;
+
 	if (!calltip_provider)
 		calltip_provider.reset(new agi::CalltipProvider);
 
-	std::string text = GetTextRaw().data();
-	auto tokens = agi::ass::TokenizeDialogueBody(text);
-	int pos = GetCurrentPos();
-
-	agi::Calltip new_calltip = calltip_provider->GetCalltip(tokens, text, GetCurrentPos());
+	agi::Calltip new_calltip = calltip_provider->GetCalltip(tokenized_line, line_text, pos);
 
 	if (new_calltip.text.empty()) {
 		CallTipCancel();
@@ -256,15 +259,15 @@ void SubsTextEditCtrl::UpdateCallTip(wxStyledTextEvent &) {
 	CallTipSetHighlight(new_calltip.highlight_start, new_calltip.highlight_end);
 }
 
-void SubsTextEditCtrl::SetTextTo(wxString text) {
+void SubsTextEditCtrl::SetTextTo(wxString const& text) {
 	SetEvtHandlerEnabled(false);
 	Freeze();
 
 	int from=0,to=0;
 	GetSelection(&from,&to);
 
+	line_text.clear();
 	SetText(text);
-	UpdateStyle();
 
 	// Restore selection
 	SetSelectionU(GetReverseUnicodePosition(from), GetReverseUnicodePosition(to));
@@ -290,7 +293,6 @@ void SubsTextEditCtrl::Paste() {
 	int sel_start = GetUnicodePosition(from + data.size());
 	SetSelectionStart(sel_start);
 	SetSelectionEnd(sel_start);
-	UpdateStyle();
 }
 
 void SubsTextEditCtrl::OnContextMenu(wxContextMenuEvent &event) {
diff --git a/aegisub/src/subs_edit_ctrl.h b/aegisub/src/subs_edit_ctrl.h
index 8f873fc55..00cf6983e 100644
--- a/aegisub/src/subs_edit_ctrl.h
+++ b/aegisub/src/subs_edit_ctrl.h
@@ -47,6 +47,7 @@ namespace agi {
 	class CalltipProvider;
 	class SpellChecker;
 	struct Context;
+	namespace ass { struct DialogueToken; }
 }
 
 /// @class SubsTextEditCtrl
@@ -82,6 +83,16 @@ class SubsTextEditCtrl : public ScintillaTextCtrl {
 	/// Position of the currently show calltip
 	size_t calltip_position;
 
+	/// Cursor position which the current calltip is for
+	int cursor_pos;
+
+	/// The last seen line text, used to avoid reparsing the line for syntax
+	/// highlighting when possible
+	std::string line_text;
+
+	/// Tokenized version of line_text
+	std::vector<agi::ass::DialogueToken> tokenized_line;
+
 	void OnContextMenu(wxContextMenuEvent &);
 	void OnAddToDictionary(wxCommandEvent &event);
 	void OnUseSuggestion(wxCommandEvent &event);
@@ -94,7 +105,7 @@ class SubsTextEditCtrl : public ScintillaTextCtrl {
 	void Subscribe(std::string const& name);
 
 	void StyleSpellCheck();
-	void UpdateCallTip(wxStyledTextEvent &);
+	void UpdateCallTip();
 	void SetStyles();
 
 	void UpdateStyle();
@@ -115,7 +126,7 @@ public:
 	SubsTextEditCtrl(wxWindow* parent, wxSize size, long style, agi::Context *context);
 	~SubsTextEditCtrl();
 
-	void SetTextTo(wxString text);
+	void SetTextTo(wxString const& text);
 	void Paste();
 
 	DECLARE_EVENT_TABLE()