diff --git a/app/proc_editor_micromap.pas b/app/proc_editor_micromap.pas
index 3e5947ab74c..5c2e0f88f84 100644
--- a/app/proc_editor_micromap.pas
+++ b/app/proc_editor_micromap.pas
@@ -133,6 +133,7 @@ procedure EditorPaintMicromap(Ed: TATSynEdit; ACanvas: TCanvas; const ARect: TRe
   if Ed.OptLastLineOnTop then
     NScaleDiv:= Max(1, NScaleDiv+Ed.GetVisibleLines-1);
 
+  //decrement NRectHeight if editor has too many lines
   NRectHeight:= ARect.Height;
   i:= Ed.GetVisibleLines * NRectHeight div NScaleDiv;
   if i < UiOps.MicromapMinViewareaHeight then