Are you using the latest version of the control (5.0.86)? As I remember, we had this problem some years ago, but it has been already fixed.
If it still occurs in the v5.0.86, send us a project we can launch to reproduce the bug, please.
As for a method one can use to align column headers and columns, there is no such a method as this problem should never occur, so we will be glad to fix this bug ASAP if it is still present in iGrid.