If fixed_width is not -1, sets the fixed width of tree_column; otherwise
unsets it. The effective value of fixed_width is clamped between the
minumum and maximum width of the column; however, the value stored in the
"fixed-width" property is not clamped. If the column sizing is
GTK_TREE_VIEW_COLUMN_GROW_ONLY or GTK_TREE_VIEW_COLUMN_AUTOSIZE, setting a
fixed width overrides the automatically calculated width. Note that
fixed_width is only a hint to GTK+; the width actually allocated to the
column may be greater or less than requested.
Along with "expand", the "fixed-width" property changes when the column is
resized by the user.
If fixed_width is not -1, sets the fixed width of tree_column; otherwise unsets it. The effective value of fixed_width is clamped between the minumum and maximum width of the column; however, the value stored in the "fixed-width" property is not clamped. If the column sizing is GTK_TREE_VIEW_COLUMN_GROW_ONLY or GTK_TREE_VIEW_COLUMN_AUTOSIZE, setting a fixed width overrides the automatically calculated width. Note that fixed_width is only a hint to GTK+; the width actually allocated to the column may be greater or less than requested. Along with "expand", the "fixed-width" property changes when the column is resized by the user.