Are you talking about the column widths in the new mail message folder? If so, resizing the columns should be sticky but obviously it isn't. Do all other folder windows open with the same column widths? If so, there might be a default window layout that needs to be changed. To do this, resize the columns then set the window layout as default. That setting is located in Folder > Default size and layout. Note, the Folder menu is dynamic based on the type of window that is active at the time.
Are you talking about the column widths in the new mail message folder?  If so, resizing the columns should be sticky but obviously it isn't.  Do all other folder windows open with the same column widths?  If so, there might be a default window layout that needs to be changed.  To do this, resize the columns then set the window layout as default.  That setting is located in Folder > Default size and layout.  Note, the Folder menu is dynamic based on the type of window that is active at the time.