fix: pre-select nothing in BOOL grid cell editor on PostgreSQL

Refs #1290

Author: ansgarbecker

source/dbconnection.pas

@@ -8911,8 +8911,8 @@ function TPGQuery.Col(Column: Integer; IgnoreErrors: Boolean=False): String;
       SetString(AnsiStr, FConnection.Lib.PQgetvalue(FCurrentResults, FRecNoLocal, Column), FColumnLengths[Column]);
       if Datatype(Column).Category in [dtcBinary, dtcSpatial] then
         Result := String(AnsiStr)
-      else if Datatype(Column).Index = dbdtBool then
-        if AnsiStr='t' then Result := 'true' else Result := 'false'
+      else if (Datatype(Column).Index = dbdtBool) and (Length(AnsiStr) > 0) then
+        Result := IfThen(AnsiStr='t', 'true', 'false')
       else
         Result := Connection.DecodeAPIString(AnsiStr);
     end;

source/main.pas

@@ -10371,8 +10371,10 @@ procedure TMainForm.AnyGridGetText(Sender: TBaseVirtualTree; Node: PVirtualNode;
 
   RowNumber := Sender.GetNodeData(Node);
   Results.RecNo := RowNumber^;
-  if Results.IsNull(ResultCol) and (not EditingAndFocused) then
-    CellText := TEXT_NULL
+  if Results.IsNull(ResultCol) then begin
+    // Grid editors come here through Tree.GetTextInfo(), provide empty string then
+    CellText := IfThen(EditingAndFocused, '', TEXT_NULL);
+  end
   else begin
     case Results.DataType(ResultCol).Category of
       dtcInteger, dtcReal: begin