I have a quite simple problem: use manipulate to create and edit a table with identifiers in first column and abbreviations in second column. I am new with manipulate and dynamic modules. I have written a code that works.

ClearAll["Global`*"]
low = CharacterRange["a", "g"];
nRows = 4;
abb[r_] := Table[
   ToExpression["R" <> ToString[r] <> low[[i]]] -> low[[i]], {i, 1, 
    Length[low]}];
row[r_] := {ToExpression["Row" <> ToString[r]], 
  ToExpression["R" <> ToString[r] <> "a"], abb[r]}
rec[{id_, abb_, ru_}] := {id, 
  ToExpression[StringTake[ToString[abb], -1]]}
file = Table[row[r], {r, 1, nRows}];
control[{id_, abbr_, rules_}] := {
  InputField[Dynamic[id]],
  PopupMenu[Dynamic[abbr], rules]
  }
Manipulate[
 MatrixForm[Map[rec, file]],
 Grid[Map[control, file]],
 ContinuousAction -> None,
 ControlPlacement -> Left
 ]

But I find it much too complicated. Would there be a more natural way to proceed? Is it possible to avoid using the update button. Thanks