diff --git a/src/event.rs b/src/event.rs
index f69136df..c9043a06 100644
--- a/src/event.rs
+++ b/src/event.rs
@@ -336,6 +336,7 @@ impl<N: Notify> Processor<N> {
                         if ref_test {
                             // dump grid state
                             let mut grid = processor.ctx.terminal.grid().clone();
+                            grid.initialize_all(&::term::cell::Cell::default());
                             grid.truncate();
 
                             let serialized_grid = json::to_string(&grid)
@@ -344,6 +345,11 @@ impl<N: Notify> Processor<N> {
                             let serialized_size = json::to_string(processor.ctx.terminal.size_info())
                                 .expect("serialize size");
 
+                            let serialized_config = format!(
+                                "{{\"history_size\":{}}}",
+                                grid.history_size()
+                            );
+
                             File::create("./grid.json")
                                 .and_then(|mut f| f.write_all(serialized_grid.as_bytes()))
                                 .expect("write grid.json");
@@ -351,6 +357,10 @@ impl<N: Notify> Processor<N> {
                             File::create("./size.json")
                                 .and_then(|mut f| f.write_all(serialized_size.as_bytes()))
                                 .expect("write size.json");
+
+                            File::create("./config.json")
+                                .and_then(|mut f| f.write_all(serialized_config.as_bytes()))
+                                .expect("write config.json");
                         }
 
                         // FIXME should do a more graceful shutdown
diff --git a/src/grid/mod.rs b/src/grid/mod.rs
index b6313751..113445af 100644
--- a/src/grid/mod.rs
+++ b/src/grid/mod.rs
@@ -435,6 +435,20 @@ impl<T> Grid<T> {
         self.raw.len()
     }
 
+    #[inline]
+    pub fn history_size(&self) -> usize {
+        self.raw.len().saturating_sub(*self.lines)
+    }
+
+    /// This is used only for initializing after loading ref-tests
+    pub fn initialize_all(&mut self, template: &T)
+    where
+        T: Copy
+    {
+        let history_size = self.raw.len().saturating_sub(*self.lines);
+        self.raw.initialize(self.max_scroll_limit - history_size, Row::new(self.cols, template));
+    }
+
     /// This is used only for truncating before saving ref-tests
     pub fn truncate(&mut self) {
         self.raw.truncate();
diff --git a/tests/ref.rs b/tests/ref.rs
index 74cac6fa..0e059670 100644
--- a/tests/ref.rs
+++ b/tests/ref.rs
@@ -99,12 +99,13 @@ fn ref_test(dir: &Path) {
 
     // Truncate invisible lines from the grid
     let mut term_grid = terminal.grid().clone();
+    term_grid.initialize_all(&Cell::default());
     term_grid.truncate();
 
     if grid != term_grid {
         for i in 0..grid.len() {
             for j in 0..grid.num_cols().0 {
-                let cell = terminal.grid()[i][Column(j)];
+                let cell = term_grid[i][Column(j)];
                 let original_cell = grid[i][Column(j)];
                 if original_cell != cell {
                     println!("[{i}][{j}] {original:?} => {now:?}",