Enables or disables the fixed height mode of @tree_view.
Fixed height mode speeds up GtkTreeView by assuming that all
rows have the same height.
Only enable this option if all rows are the same height and all
columns are of type %GTK_TREE_VIEW_COLUMN_FIXED.
Enables or disables the fixed height mode of @tree_view. Fixed height mode speeds up GtkTreeView by assuming that all rows have the same height. Only enable this option if all rows are the same height and all columns are of type %GTK_TREE_VIEW_COLUMN_FIXED.