diff --git a/lcl/valedit.pas b/lcl/valedit.pas
index f378e74f6a..4bae0cf034 100644
--- a/lcl/valedit.pas
+++ b/lcl/valedit.pas
@@ -1076,14 +1076,17 @@ procedure TValueListEditor.AdjustColumnWidths;
 // If key column is fixed in width then adjust only the second column,
 //  otherwise adjust both columns propertionally.
 var
-  CW, AWidth: Integer;
+  CW, AWidth, BWidth: Integer;
 begin
   CW := ClientWidth;
   if  (doKeyColFixed in DisplayOptions) then
   begin
     //AutoSizeColumn(0);
-    If ColWidths[0] > CW Then
-      ColWidths[0] := CW - 1;
+    If ColWidths[0] > CW Then Begin
+      BWidth := CW - 1;
+      If BWidth > 0 Then
+        ColWidths[0] := BWidth;
+    end;
     AWidth := CW - ColWidths[0];
     If AWidth > 0 Then
       ColWidths[1] := AWidth;