diff --git a/imgui.cpp b/imgui.cpp
index 03c3cfc..caef89e 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -6550,7 +6550,8 @@
     if (c < (int)IndexLookup.size())
     {
         const int i = IndexLookup[c];
-        return &Glyphs[i];
+        if (i != -1)
+            return &Glyphs[i];
     }
     return FallbackGlyph;
 }