Support double_width chars

src/ui_model/model_rect.rs

@@ -108,6 +108,24 @@ impl ModelRect {
             if right < self.right + len_since_right {
                 right = self.right + len_since_right;
             }
+
+            // extend also double_width chars
+            let cell = &line.line[self.left];
+            if self.left > 0 && cell.attrs.double_width {
+                let dw_char_idx = self.left - 1;
+                if dw_char_idx < left {
+                    left = dw_char_idx;
+                }
+            }
+
+            let dw_char_idx = self.right + 1;
+            if let Some(cell) = line.line.get(dw_char_idx) {
+                if cell.attrs.double_width {
+                    if right < dw_char_idx {
+                        right = dw_char_idx;
+                    }
+                }
+            }
         }
 
         self.left = left;