Mail Tool Window Size

Use the Display Headers field to determine how many headers are displayed in your primary Mail Tool Header window. You can increase the setting to display more headers at one time, or decrease the setting to display fewer headers to make the Header window smaller.

Use the Display Characters field to determine the width of all Mail Tool panels and windows.

After you make changes to the Display fields, you need to quit the Mail Tool application and restart it in order to see the change.