diff --git a/src/subs_edit_box.cpp b/src/subs_edit_box.cpp
index ee1625dd3..c042d32bf 100644
--- a/src/subs_edit_box.cpp
+++ b/src/subs_edit_box.cpp
@@ -201,10 +201,15 @@ SubsEditBox::SubsEditBox(wxWindow *parent, agi::Context *context)
 	main_sizer->Add(middle_right_sizer,0,wxEXPAND | wxLEFT | wxRIGHT | wxBOTTOM,3);
 
 	// Text editor
-	edit_ctrl = new SubsTextEditCtrl(this, wxSize(-1, 50), wxBORDER_SUNKEN, c);
+	edit_ctrl = new SubsTextEditCtrl(this, wxDefaultSize, wxBORDER_SUNKEN, c);
 	edit_ctrl->Bind(wxEVT_CHAR_HOOK, &SubsEditBox::OnKeyDown, this);
 
-	secondary_editor = new wxTextCtrl(this, -1, "", wxDefaultPosition, wxSize(-1, 50), wxBORDER_SUNKEN | wxTE_MULTILINE | wxTE_READONLY);
+	secondary_editor = new wxTextCtrl(this, -1, "", wxDefaultPosition, wxDefaultSize, wxBORDER_SUNKEN | wxTE_MULTILINE | wxTE_READONLY);
+	// Here we use the height of secondary_editor as the initial size of edit_ctrl,
+	// which is more reasonable than the default given by wxWidgets.
+	// See: https://trac.wxwidgets.org/ticket/18471#ticket
+	//      https://github.com/wangqr/Aegisub/issues/4
+	edit_ctrl->SetInitialSize(secondary_editor->GetSize());
 
 	main_sizer->Add(secondary_editor,1,wxEXPAND | wxLEFT | wxRIGHT | wxBOTTOM,3);
 	main_sizer->Add(edit_ctrl,1,wxEXPAND | wxLEFT | wxRIGHT | wxBOTTOM,3);