If @resizable is %TRUE, then the user can explicitly resize the column by
grabbing the outer edge of the column button. If resizable is %TRUE and
sizing mode of the column is #GTK_TREE_VIEW_COLUMN_AUTOSIZE, then the sizing
mode is changed to #GTK_TREE_VIEW_COLUMN_GROW_ONLY.
If @resizable is %TRUE, then the user can explicitly resize the column by grabbing the outer edge of the column button. If resizable is %TRUE and sizing mode of the column is #GTK_TREE_VIEW_COLUMN_AUTOSIZE, then the sizing mode is changed to #GTK_TREE_VIEW_COLUMN_GROW_ONLY.