diff --git a/src/shell.rs b/src/shell.rs
index 916e2c4..005eb6f 100644
--- a/src/shell.rs
+++ b/src/shell.rs
@@ -1182,8 +1182,7 @@ impl State {
     pub fn on_put(&mut self, text: String) -> RepaintMode {
         let double_width = text.is_empty();
         RepaintMode::Area(
-            self.model
-                .put(Some(text), double_width, self.cur_attrs.as_ref()),
+            self.model.put(&text, double_width, self.cur_attrs.as_ref()),
         )
     }
 
diff --git a/src/ui_model/cell.rs b/src/ui_model/cell.rs
index 7bd07d1..5d9f3e9 100644
--- a/src/ui_model/cell.rs
+++ b/src/ui_model/cell.rs
@@ -79,7 +79,7 @@ impl Attrs {
 #[derive(Clone)]
 pub struct Cell {
     pub attrs: Attrs,
-    pub ch: Option<String>,
+    pub ch: String,
     pub dirty: bool,
 }
 
@@ -87,13 +87,13 @@ impl Cell {
     pub fn new_empty() -> Cell {
         Cell {
             attrs: Attrs::new(),
-            ch: None,
+            ch: String::new(),
             dirty: true,
         }
     }
 
     pub fn clear(&mut self) {
-        self.ch = None;
+        self.ch.clear();
         self.attrs.clear();
         self.dirty = true;
     }
diff --git a/src/ui_model/line.rs b/src/ui_model/line.rs
index 12092f4..5061df9 100644
--- a/src/ui_model/line.rs
+++ b/src/ui_model/line.rs
@@ -254,7 +254,11 @@ impl StyledLine {
                 continue;
             }
 
-            line_str.push_str(cell.ch.as_ref().map(|ch| ch.as_str()).unwrap_or(" "));
+            if !cell.ch.is_empty() {
+                line_str.push_str(&cell.ch);
+            } else {
+                line_str.push(' ');
+            }
             let len = line_str.len() - byte_offset;
 
             for _ in 0..len {
@@ -399,9 +403,9 @@ mod tests {
     #[test]
     fn test_styled_line() {
         let mut line = Line::new(3);
-        line[0].ch = Some("a".to_owned());
-        line[1].ch = Some("b".to_owned());
-        line[2].ch = Some("c".to_owned());
+        line[0].ch = "a".to_owned();
+        line[1].ch = "b".to_owned();
+        line[2].ch = "c".to_owned();
 
         let styled_line = StyledLine::from(&line, &color::ColorModel::new());
         assert_eq!("abc", styled_line.line_str);
diff --git a/src/ui_model/mod.rs b/src/ui_model/mod.rs
index 823751f..b9273f4 100644
--- a/src/ui_model/mod.rs
+++ b/src/ui_model/mod.rs
@@ -93,14 +93,16 @@ impl UiModel {
         (self.cur_row, self.cur_col)
     }
 
-    pub fn put(&mut self, ch: Option<String>, double_width: bool, attrs: Option<&Attrs>) -> ModelRect {
+    pub fn put(&mut self, ch: &str, double_width: bool, attrs: Option<&Attrs>) -> ModelRect {
         let mut changed_region = self.cur_point();
         let line = &mut self.model[self.cur_row];
         line.dirty_line = true;
 
         let cell = &mut line[self.cur_col];
 
-        cell.ch = ch;
+        cell.ch.clear();
+        cell.ch.push_str(ch);
+
         cell.attrs = attrs.map(Attrs::clone).unwrap_or_else(Attrs::new);
         cell.attrs.double_width = double_width;
         cell.dirty = true;
@@ -305,7 +307,7 @@ mod tests {
 
         model.set_cursor(1, 1);
 
-        let rect = model.put(Some(" ".to_owned()), false, None);
+        let rect = model.put(" ", false, None);
 
         assert_eq!(1, rect.top);
         assert_eq!(1, rect.left);
diff --git a/src/ui_model/model_layout.rs b/src/ui_model/model_layout.rs
index 6307021..c577ad0 100644
--- a/src/ui_model/model_layout.rs
+++ b/src/ui_model/model_layout.rs
@@ -78,7 +78,7 @@ impl ModelLayout {
             self.insert_into_lines(ch);
             self.layout_replace(0, 0);
         } else {
-            self.model.put(Some(ch), false, None);
+            self.model.put(&ch, false, None);
         }
 
         self.model.set_cursor(row, col);
@@ -126,9 +126,9 @@ impl ModelLayout {
                     }
 
                     self.model.set_cursor(row_idx, col_idx as usize);
-                    self.model.put(Some(ch.clone()), false, attr.as_ref());
+                    self.model.put(ch, false, attr.as_ref());
                     if ch_width > 1 {
-                        self.model.put(None, true, attr.as_ref());
+                        self.model.put("", true, attr.as_ref());
                     }
 
                     if max_col_idx < col_idx {
@@ -220,7 +220,7 @@ mod tests {
 
         let (cols, _) = model.size();
         assert_eq!(4, cols);
-        assert_eq!(Some("b".to_owned()), model.model.model()[0].line[1].ch);
+        assert_eq!("b", model.model.model()[0].line[1].ch);
     }
 
     #[test]
@@ -234,7 +234,7 @@ mod tests {
 
         let (cols, _) = model.size();
         assert_eq!(3, cols);
-        assert_eq!(Some("b".to_owned()), model.model.model()[0].line[1].ch);
+        assert_eq!("b", model.model.model()[0].line[1].ch);
     }
 
     #[test]