Using convenience method and using extended clusters as recommended.

src/column.rs

@@ -86,7 +86,7 @@ impl Cell {
     pub fn paint(style: Style, string: &str) -> Cell {
         Cell {
             text: style.paint(string).to_string(),
-            length: string.graphemes(true).count(),
+            length: string.width(true),
         }
     }
 }

src/file.rs

@@ -173,7 +173,7 @@ impl<'a> File<'a> {
     /// characters are 1 columns wide, but in some contexts, certain
     /// characters are actually 2 columns wide.
     pub fn file_name_width(&self) -> usize {
-        self.name.as_slice().width(false)
+        self.name.as_slice().width(true)
     }
 
     /// Assuming the current file is a symlink, follows the link and