diff --git a/fpdfsdk/cfx_systemhandler.cpp b/fpdfsdk/cfx_systemhandler.cpp
index 95a940d..c5f5334 100644
--- a/fpdfsdk/cfx_systemhandler.cpp
+++ b/fpdfsdk/cfx_systemhandler.cpp
@@ -126,17 +126,13 @@
 }
 
 bool CFX_SystemHandler::IsSHIFTKeyDown(uint32_t nFlag) const {
-  return m_pEnv->FFI_IsSHIFTKeyDown(nFlag);
+  return !!m_pEnv->FFI_IsSHIFTKeyDown(nFlag);
 }
 
 bool CFX_SystemHandler::IsCTRLKeyDown(uint32_t nFlag) const {
-  return m_pEnv->FFI_IsCTRLKeyDown(nFlag);
+  return !!m_pEnv->FFI_IsCTRLKeyDown(nFlag);
 }
 
 bool CFX_SystemHandler::IsALTKeyDown(uint32_t nFlag) const {
-  return m_pEnv->FFI_IsALTKeyDown(nFlag);
-}
-
-bool CFX_SystemHandler::IsINSERTKeyDown(uint32_t nFlag) const {
-  return m_pEnv->FFI_IsINSERTKeyDown(nFlag);
+  return !!m_pEnv->FFI_IsALTKeyDown(nFlag);
 }
diff --git a/fpdfsdk/cfx_systemhandler.h b/fpdfsdk/cfx_systemhandler.h
index ec57353..e77120a 100644
--- a/fpdfsdk/cfx_systemhandler.h
+++ b/fpdfsdk/cfx_systemhandler.h
@@ -68,7 +68,6 @@
   bool IsSHIFTKeyDown(uint32_t nFlag) const;
   bool IsCTRLKeyDown(uint32_t nFlag) const;
   bool IsALTKeyDown(uint32_t nFlag) const;
-  bool IsINSERTKeyDown(uint32_t nFlag) const;
 
   FX_SYSTEMTIME GetLocalTime();
 
diff --git a/fpdfsdk/include/fsdk_mgr.h b/fpdfsdk/include/fsdk_mgr.h
index 8fbc0d7..cd89a92 100644
--- a/fpdfsdk/include/fsdk_mgr.h
+++ b/fpdfsdk/include/fsdk_mgr.h
@@ -115,8 +115,6 @@
     return (nFlag & FWL_EVENTFLAG_AltKey) != 0;
   }
 
-  FX_BOOL FFI_IsINSERTKeyDown(uint32_t nFlag) const { return FALSE; }
-
   FPDF_PAGE FFI_GetPage(FPDF_DOCUMENT document, int nPageIndex) {
     if (m_pInfo && m_pInfo->FFI_GetPage)
       return m_pInfo->FFI_GetPage(m_pInfo, document, nPageIndex);
diff --git a/fpdfsdk/pdfwindow/PWL_EditCtrl.cpp b/fpdfsdk/pdfwindow/PWL_EditCtrl.cpp
index a659658..23349b4 100644
--- a/fpdfsdk/pdfwindow/PWL_EditCtrl.cpp
+++ b/fpdfsdk/pdfwindow/PWL_EditCtrl.cpp
@@ -284,8 +284,6 @@
     case FWL_VKEY_Unknown:
       break;
     default:
-      if (IsINSERTpressed(nFlag))
-        Delete();
       InsertWord(word, GetCharSet());
       break;
   }
diff --git a/fpdfsdk/pdfwindow/PWL_Wnd.cpp b/fpdfsdk/pdfwindow/PWL_Wnd.cpp
index 8883ceb..bb424ff 100644
--- a/fpdfsdk/pdfwindow/PWL_Wnd.cpp
+++ b/fpdfsdk/pdfwindow/PWL_Wnd.cpp
@@ -1029,11 +1029,3 @@
 
   return FALSE;
 }
-
-FX_BOOL CPWL_Wnd::IsINSERTpressed(uint32_t nFlag) const {
-  if (CFX_SystemHandler* pSystemHandler = GetSystemHandler()) {
-    return pSystemHandler->IsINSERTKeyDown(nFlag);
-  }
-
-  return FALSE;
-}
diff --git a/fpdfsdk/pdfwindow/PWL_Wnd.h b/fpdfsdk/pdfwindow/PWL_Wnd.h
index dec3f9f..319e6da 100644
--- a/fpdfsdk/pdfwindow/PWL_Wnd.h
+++ b/fpdfsdk/pdfwindow/PWL_Wnd.h
@@ -425,7 +425,6 @@
   FX_BOOL IsCTRLpressed(uint32_t nFlag) const;
   FX_BOOL IsSHIFTpressed(uint32_t nFlag) const;
   FX_BOOL IsALTpressed(uint32_t nFlag) const;
-  FX_BOOL IsINSERTpressed(uint32_t nFlag) const;
 
  private:
   void AddChild(CPWL_Wnd* pWnd);