Width of row selector (serial no. column)

Dear all.

I want to increase the width of the row selector i.e. the serial number column of the grid.

So, I tried adding width field to the grid definition as given below.

#myGrid .aw-row-selector {text-align: center; width: 50px;}

But it was not of much help.

How could I increase the width of the row selector i.e. the serial number column of the grid?