https://docs.wxwidgets.org/3.0/classwx_combo_box.html#a41789d188664ce4d05500b8452798c8f

Index: src/hist_val.cpp
--- src/hist_val.cpp.orig
+++ src/hist_val.cpp
@@ -113,7 +113,7 @@ HistoryValidator::TransferToWindow()
       }
 
       // if we have an entry, select it
-      if (!comboBox->IsEmpty())
+      if (!comboBox->IsTextEmpty())
         comboBox->SetSelection(0, 0);
     }
 
