+Sets the widths of the fields in the status line. There are two types of
+fields: fixed widths one and variable width fields. For the fixed width fields
+you should specify their (constant) width in pixels. For the variable width
+fields, specify a negative number which indicates how should the field expand:
+the space left for all variable width fields is divided between them according
+to the absolute value of this number. A variable width field with width of $-2$
+gets twice as much of it as a field with width $-1$ and so on.
+
+For example, to create one fixed width field of width $50$ in the right part of
+the status bar and two more fields which get $66$\% and $33$\% of the remaining
+space correspondingly, you should use an array containing $-2$, $-1$ and $100$.