diff --git a/fpdfsdk/fpdf_edittext.cpp b/fpdfsdk/fpdf_edittext.cpp
index ca4d6f7..2478c23 100644
--- a/fpdfsdk/fpdf_edittext.cpp
+++ b/fpdfsdk/fpdf_edittext.cpp
@@ -351,7 +351,8 @@
     if (currentChar > kMaxUnicode)
       break;
 
-    widths[glyphIndex] = pFont->GetGlyphWidth(glyphIndex);
+    if (!pdfium::ContainsKey(widths, glyphIndex))
+      widths[glyphIndex] = pFont->GetGlyphWidth(glyphIndex);
     to_unicode[glyphIndex] = currentChar;
     currentChar =
         FXFT_Get_Next_Char(pFont->GetFace(), currentChar, &glyphIndex);