my ($columns, $rows) = $main_window -> gridSize();

for (my$i = 0; $i < $columns; $i++) {
  $main_window -> gridColumnconfigure($i, -weight => 1);
}
for (my$i = 0; $i < $rows; $i++) {
  $main_window -> gridRowconfigure($i, -weight => 1);
}