diff --git a/src/render/context.rs b/src/render/context.rs
index f5ff9ca..ff356a1 100644
--- a/src/render/context.rs
+++ b/src/render/context.rs
@@ -22,7 +22,7 @@ impl Context {
     }
 
     pub fn itemize(&self, line: &StyledLine) -> Vec<sys_pango::Item> {
-        sys_pango::pango_itemize(&self.pango_context, &line.line_str, &line.attr_list)
+        sys_pango::pango_itemize(&self.pango_context, line.line_str.trim_right(), &line.attr_list)
     }
 }
 
diff --git a/src/render/mod.rs b/src/render/mod.rs
index 482539d..50f75e2 100644
--- a/src/render/mod.rs
+++ b/src/render/mod.rs
@@ -52,7 +52,6 @@ pub fn shape_dirty(ctx: &context::Context, ui_model: &mut ui_model::UiModel) {
 
             for i in 0..line.line.len() {
                 if line[i].dirty {
-                    // FIXME: dont shape/render empty items(space cells)
                     if let Some(mut item) = line.get_item_mut(i) {
                         let mut glyphs = pango::GlyphString::new();
                         {
diff --git a/src/sys/pango/item.rs b/src/sys/pango/item.rs
index 015cd88..aadaf94 100644
--- a/src/sys/pango/item.rs
+++ b/src/sys/pango/item.rs
@@ -39,4 +39,8 @@ impl Item {
     pub fn offset(&self) -> (usize, usize, usize) {
         (self.0.offset as usize, self.0.length as usize, self.0.num_chars as usize)
     }
+
+    pub fn length(&self) -> i32 {
+        self.0.length
+    }
 }
diff --git a/src/sys/pango/mod.rs b/src/sys/pango/mod.rs
index f5dc4a5..01c0788 100644
--- a/src/sys/pango/mod.rs
+++ b/src/sys/pango/mod.rs
@@ -13,7 +13,7 @@ use glib::translate::*;
 
 pub fn pango_itemize(
     context: &pango::Context,
-    text: &String,
+    text: &str,
     attrs: &pango::AttrList
 ) -> Vec<Item> {
     unsafe {
@@ -29,7 +29,7 @@ pub fn pango_itemize(
 }
 
 pub fn pango_shape(
-    text: &String,
+    text: &str,
     offset: usize,
     length: usize,
     analysis: &Analysis,
diff --git a/src/ui_model/line.rs b/src/ui_model/line.rs
index ef613e0..ea0fa1e 100644
--- a/src/ui_model/line.rs
+++ b/src/ui_model/line.rs
@@ -75,6 +75,13 @@ impl Line {
         }
     }
 
+    pub fn copy_to(&self, target: &mut Self, left: usize, right: usize) {
+        target.line[left..right + 1].clone_from_slice(&self.line[left..right + 1]);
+        // don't update items, but mark line as dirty to force item recalculation
+        // all work must be done in merge function
+        target.dirty_line = true;
+    }
+
     pub fn clear(&mut self, left: usize, right: usize) {
         for cell in &mut self.line[left..right + 1] {
             cell.clear();
@@ -93,30 +100,41 @@ impl Line {
         }
     }
 
-    fn set_cell_to_item(&mut self, pango_item: &PangoItemPosition) -> bool {
-        let start_item = self.cell_to_item(pango_item.start_cell);
-        let end_item = self.cell_to_item(pango_item.end_cell);
-        //FIXME: check start cell
-        //FIXME: check length
-        //FIXME: don't check start_item != end_item
+    fn set_cell_to_item(&mut self, new_item: &PangoItemPosition) -> bool {
+        let start_item_idx = self.cell_to_item(new_item.start_cell);
+        let start_item_len = if start_item_idx > 0 {
+            self.item_line[start_item_idx as usize]
+                .as_ref()
+                .unwrap()
+                .item
+                .length()
+        } else {
+            -1
+        };
 
+        let end_item_idx = self.cell_to_item(new_item.end_cell);
+
+        // start_item == idx of item start cell
         // in case different item length was in previous iteration
         // mark all item as dirty
-        if start_item != end_item || start_item == -1 || end_item == -1 {
-            self.initialize_cell_item(pango_item.start_cell, pango_item.end_cell, pango_item.item);
+        if start_item_idx != new_item.start_cell as i32 ||
+            new_item.item.length() != start_item_len || start_item_idx == -1 ||
+            end_item_idx == -1
+        {
+            self.initialize_cell_item(new_item.start_cell, new_item.end_cell, new_item.item);
             true
         } else {
             // update only if cell marked as dirty
-            if self.line[pango_item.start_cell..pango_item.end_cell + 1]
+            if self.line[new_item.start_cell..new_item.end_cell + 1]
                 .iter()
                 .find(|c| c.dirty)
                 .is_some()
             {
-                self.item_line[pango_item.start_cell]
+                self.item_line[new_item.start_cell]
                     .as_mut()
                     .unwrap()
-                    .update(pango_item.item.clone());
-                self.line[pango_item.start_cell].dirty = true;
+                    .update(new_item.item.clone());
+                self.line[new_item.start_cell].dirty = true;
                 true
             } else {
                 false
diff --git a/src/ui_model/mod.rs b/src/ui_model/mod.rs
index 6a5864d..342fa64 100644
--- a/src/ui_model/mod.rs
+++ b/src/ui_model/mod.rs
@@ -123,12 +123,24 @@ impl UiModel {
     }
 
     #[inline]
-    fn copy_row(&mut self, row: i64, offset: i64, left: usize, right: usize) {
-        for col in left..right + 1 {
-            let from_row = (row + offset) as usize;
-            let from_cell = self.model[from_row][col].clone();
-            self.model[row as usize][col] = from_cell;
-        }
+    fn copy_row(&mut self, target_row: i64, offset: i64, left_col: usize, right_col: usize) {
+        debug_assert!(offset != 0);
+
+        let from_row = (target_row + offset) as usize;
+
+        let (left, right) = if offset > 0 {
+            self.model.split_at_mut(from_row)
+        } else {
+            self.model.split_at_mut(target_row as usize)
+        };
+
+        let (source_row, target_row) = if offset > 0 {
+            (&right[0], &mut left[target_row as usize])
+        } else {
+            (&left[from_row], &mut right[0])
+        };
+
+        source_row.copy_to(target_row, left_col, right_col);
     }
 
     pub fn scroll(&mut self, count: i64) -> ModelRect {