diff --git a/src/stc/PlatWX.cpp b/src/stc/PlatWX.cpp
index 11795fe591..03b33aaadc 100644
--- a/src/stc/PlatWX.cpp
+++ b/src/stc/PlatWX.cpp
@@ -2224,7 +2224,7 @@ PRectangle Window::GetMonitorRect(Point pt) {
 #endif // __WXOSX_COCOA__
 
 wxSTCPopupWindow::wxSTCPopupWindow(wxWindow* parent)
-                 :wxSTCPopupBase(parent), m_initialPosition(wxDefaultPosition)
+                 :wxSTCPopupBase(parent), m_lastKnownPosition(wxDefaultPosition)
 {
     #if !wxSTC_POPUP_IS_CUSTOM
         Bind(wxEVT_SET_FOCUS, &wxSTCPopupWindow::OnFocus, this);
@@ -2275,9 +2275,7 @@ bool wxSTCPopupWindow::AcceptsFocus() const
 
 void wxSTCPopupWindow::DoSetSize(int x, int y, int width, int height, int flags)
 {
-    if ( m_initialPosition == wxDefaultPosition
-            && x != wxDefaultCoord && y != wxDefaultCoord )
-        m_initialPosition = wxPoint(x, y);
+    m_lastKnownPosition = wxPoint(x, y);
 
     // convert coords to screen coords since we're a top-level window
     if (x != wxDefaultCoord)
@@ -2291,8 +2289,8 @@ void wxSTCPopupWindow::DoSetSize(int x, int y, int width, int height, int flags)
 
 void wxSTCPopupWindow::OnParentMove(wxMoveEvent& event)
 {
-    if ( m_initialPosition != wxDefaultPosition )
-        SetPosition(m_initialPosition);
+    if ( m_lastKnownPosition.IsFullySpecified() )
+        SetPosition(m_lastKnownPosition);
     event.Skip();
 }
 
diff --git a/src/stc/PlatWX.h b/src/stc/PlatWX.h
index 714f5e4180..31a11dbf4d 100644
--- a/src/stc/PlatWX.h
+++ b/src/stc/PlatWX.h
@@ -150,7 +150,7 @@ protected:
     #endif
 
 private:
-    wxPoint   m_initialPosition;
+    wxPoint   m_lastKnownPosition;
     wxWindow* m_tlw;
 };