diff --git a/central_widget.py b/central_widget.py
index 92038f5..db061bc 100644
--- a/central_widget.py
+++ b/central_widget.py
@@ -1,7 +1,7 @@
 import os
 from PyQt5.QtWidgets import QFrame, QLabel, QListWidget, QListWidgetItem, QStackedLayout, QVBoxLayout, QWidget, QGridLayout, QSpacerItem, QSizePolicy, QTreeView, QHeaderView
 from PyQt5.QtGui import QPixmap
-from PyQt5.QtCore import Qt, QSettings
+from PyQt5.QtCore import Qt, QSettings, QSize
 
 from file_handler import FileHandler
 import communicator as comm
@@ -45,6 +45,7 @@ class FileView(QWidget):
         self._view.setAlternatingRowColors(True)
         self._view.setUniformRowHeights(True)  # Allows for scrolling optimizations.
         self._view.setWindowTitle("Simple Tree Model")
+        self._view.setIconSize(QSize(20,20))
         header = self._view.header()
         header.setStretchLastSection(False)
         header.setSectionResizeMode(1, QHeaderView.ResizeToContents)
diff --git a/tree_model.py b/tree_model.py
index 9e70eb1..f2818b8 100644
--- a/tree_model.py
+++ b/tree_model.py
@@ -1,4 +1,5 @@
-from PyQt5.QtCore import QAbstractItemModel, QFile, QModelIndex, Qt
+from PyQt5.QtCore import QAbstractItemModel, QFile, QModelIndex, QSize, Qt
+from PyQt5.QtGui import QIcon
 from PyQt5.QtWidgets import QHeaderView, QTreeWidgetItem
 
 from file_handler import ItemDescriptor, NodeType
@@ -7,10 +8,9 @@ from IPython import embed
 column_names = ['Name', 'Type', 'ID', 'Value', 'Description']
 
 
-
-
-class NixTreeItem():
+class NixTreeItem(QTreeWidgetItem):
     def __init__(self, node_descriptor, file_handler, parent=None):
+        super().__init__(parent)
         self._node_descriptor = node_descriptor
         self._file_handler = file_handler
         
@@ -85,6 +85,48 @@ class BlockTreeItem(NixTreeItem):
             
         for t in self._file_handler.request_tags(self._node_descriptor.id):
             self._child_items.append(TagTreeItem(t, self._file_handler, parent=self))
+            
+        data_frames = self._file_handler.request_data_frames(self._node_descriptor.id)
+        for df in data_frames:
+            self._child_items.append(DataFrameTreeItem(df, self._file_handler, parent=self))
+        
+        sources = self._file_handler.request_sources(self._node_descriptor.id)
+        for s in sources:
+            self._child_items.append(SourceTreeItem(s, self._file_handler, parent=self))
+        self._is_loaded = True
+
+class SourceTreeItem(NixTreeItem):
+    def __init__(self, node_descriptor, file_handler, parent):
+        super().__init__(node_descriptor, file_handler, parent=parent)
+        self._is_loaded = False
+        
+    def load_children(self):
+        sources = self._file_handler.request_sources(self._node_descriptor.block_id, self._node_descriptor.id)
+        for s in sources:
+            self._child_items.append(SourceTreeItem(s, self._file_handler, parent=self))
+        self._is_loaded = True
+        
+class GroupTreeItem(NixTreeItem):
+    def __init__(self, node_descriptor, file_handler, parent):
+        super().__init__(node_descriptor, file_handler, parent=parent)
+        self._is_loaded = False
+    
+    def load_children(self):
+        self._child_items = []
+        arrays = self._file_handler.request_data_arrays(self._node_descriptor.id)
+        for a in arrays:
+            self._child_items.append(DataArrayTreeItem(a, self._file_handler, parent=self))
+            
+        for t in self._file_handler.request_tags(self._node_descriptor.id):
+            self._child_items.append(TagTreeItem(t, self._file_handler, parent=self))
+            
+        data_frames = self._file_handler.request_data_frames(self._node_descriptor.id)
+        for df in data_frames:
+            self._child_items.append(DataFrameTreeItem(df, self._file_handler, parent=self))
+        
+        sources = self._file_handler.request_sources(self._node_descriptor.id)
+        for s in sources:
+            self._child_items.append(SourceTreeItem(s, self._file_handler, parent=self))
         self._is_loaded = True
 
 class DataFrameTreeItem(NixTreeItem):
@@ -177,9 +219,8 @@ class TreeModel(QAbstractItemModel):
     def data(self, index, role):
         if not index.isValid():
             return None
-
         item = index.internalPointer()
-
+      
         if role == Qt.DisplayRole:
             return item.data(index.column())
         elif role == Qt.DecorationRole and index.column() == 0: