Select the type of Report Width you want used for the report. The Report Width essentially determines the overall width that will be used by the report headings. When printing or previewing, the maximum report width is 510. Anything that exceeds 510 will be truncated.

Automatic Select Automatic if you want the width to be the total of all columns defined on the Column Definition tab.
Fixed Width Select Fixed Width if you want the report width to be a specific width. If you select Fixed Width, you will be allowed to specify the width. The maximum width is 510. If you attempt to add columns that allow the total report width to exceed the defined width, "(Overflow)" will be displayed next to the Total Width field at the bottom right side of the Column Definition tab.