In Microsoft Dynamics AX 2012 the width property set up on column is ignored when is lower than length of label.

The issue in this case is the length of the label. You cannot set a default column width that is smaller than the label. This is because labels are different lengths in different languages, and we want each language to have a clean initial presentation, without having labels truncated.

If the user would like a shorter or wider column width, she can manually change the column size interactively without resorting to personalization or customization. She simply resizes the column in the UI and the size of the column is “remembered” by the grid and will always open to that size.

In addition, the user can choose to personalize the form and change the default width of the column. When this is done, it is considered an “end user override” and just as in the interactive approach and “the user wins” and the column should be sized according to the override value.

User settings may be cleared and ALL user preferences may be reset to their shipping defaults by choosing tools>>options>>Usage data and click on “Reset” (note, this clears all user preferences)

If you really want the Width property to be taken into account and you don’t mind that label will be truncated you can also achieve it by adding to form in init method following code:

public void init()

{

    super();

    Grid.autoSizeColumns(false);

}

If above code does not work, make sure that you have reset personalization.