diff --git a/src/core/Buffer.cc b/src/core/Buffer.cc
index de0b4dc..07606dd 100644
--- a/src/core/Buffer.cc
+++ b/src/core/Buffer.cc
@@ -39,6 +39,8 @@ void Buffer::common_initialization()
         m_eof_iterator->go_forward();
     }
     m_change_buffer = std::make_shared<GapBuffer>();
+    m_operation_level = 0;
+    m_current_operation_index = 0u;
 }
 
 void Buffer::load_empty_buffer()
@@ -157,15 +159,18 @@ bool Buffer::write_to_file(const char * filename)
 void Buffer::enter_insert_mode()
 {
     m_insert_mode = true;
+    push_operation();
 }
 
 void Buffer::exit_insert_mode()
 {
     m_insert_mode = false;
+    pop_operation();
 }
 
 void Buffer::insert_code_point(const Buffer::Iterator & position, uint32_t code_point, bool adjust_iterators)
 {
+    push_operation();
     Buffer::Iterator local_position = position;
     if ((code_point != '\n') && (size() == 0u))
     {
@@ -186,12 +191,14 @@ void Buffer::insert_code_point(const Buffer::Iterator & position, uint32_t code_
             }
         }
     }
+    pop_operation();
 }
 
 void Buffer::erase_code_point(const Buffer::Iterator & position)
 {
     if (position.valid())
     {
+        push_operation();
         Buffer::Iterator local_position = position;
         uint8_t bytes = 0u;
         uint32_t code_point = Encoding::decode(m_encoding, local_position.address(), &bytes);
@@ -205,6 +212,19 @@ void Buffer::erase_code_point(const Buffer::Iterator & position)
                 iterator->warp(-(ssize_t)bytes, lines);
             }
         }
+        pop_operation();
+    }
+}
+
+void Buffer::pop_operation()
+{
+    if (m_operation_level > 0)
+    {
+        m_operation_level--;
+        if (m_operation_level == 0)
+        {
+            save_current_operation();
+        }
     }
 }
 
@@ -276,3 +296,18 @@ void Buffer::record_change(uint8_t data[], size_t length, size_t buffer_position
     cu.insert = insert;
     m_current_change_operation->changes.push_back(cu);
 }
+
+void Buffer::save_current_operation()
+{
+    if (m_current_change_operation)
+    {
+        size_t new_change_operation_index = m_change_operations.size();
+        if (m_current_operation_index < new_change_operation_index)
+        {
+            m_change_operations[m_current_operation_index]->children.push_back(new_change_operation_index);
+        }
+        m_change_operations.push_back(m_current_change_operation);
+        m_current_change_operation = nullptr;
+        m_current_operation_index = new_change_operation_index;
+    }
+}
diff --git a/src/core/Buffer.h b/src/core/Buffer.h
index 180c54a..b650d31 100644
--- a/src/core/Buffer.h
+++ b/src/core/Buffer.h
@@ -8,6 +8,7 @@
 #include "GapBuffer.h"
 #include <string>
 #include "ChangeOperation.h"
+#include <vector>
 
 class Buffer
 {
@@ -117,6 +118,8 @@ public:
     std::string filename() const { return m_filename; }
     Iterator begin() const { return Iterator(this); }
     Iterator end() const { return *m_eof_iterator; }
+    void push_operation() { m_operation_level++; }
+    void pop_operation();
 
 protected:
     bool m_eol_at_eof;
@@ -130,6 +133,9 @@ protected:
     std::shared_ptr<Iterator> m_eof_iterator;
     std::string m_filename;
     std::shared_ptr<ChangeOperation> m_current_change_operation;
+    int m_operation_level;
+    size_t m_current_operation_index;
+    std::vector<std::shared_ptr<ChangeOperation>> m_change_operations;
 
     void common_initialization();
     bool load_from_file(const char * filename);
@@ -137,6 +143,7 @@ protected:
     bool load_from_memory(const uint8_t * data, size_t data_length);
     void load_text_in_buffer(uint8_t * buffer, size_t buffer_size, size_t data_length);
     void record_change(uint8_t data[], size_t length, size_t buffer_position, bool insert);
+    void save_current_operation();
 };
 
 #endif