diff --git a/public/algorithms/c45-tree.js b/public/algorithms/c45-tree.js
index b06ad35..25aef5f 100644
--- a/public/algorithms/c45-tree.js
+++ b/public/algorithms/c45-tree.js
@@ -55,7 +55,7 @@ function buildDecisionTreeC45(
       quality: _quality,
       matchedCount: _positiveCounter,
       notMatchedCount: _negativeCounter,
-      trainingSet2: trainingSet.map(x => x[categoryAttr]),
+      trainingSet2: trainingSet,
     };
   }
   //console.log(categoryAttr);
@@ -81,7 +81,7 @@ function buildDecisionTreeC45(
       quality: _quality,
       matchedCount: _positiveCounter,
       notMatchedCount: _negativeCounter,
-      trainingSet2: trainingSet.map(x => x[categoryAttr]),
+      trainingSet2: trainingSet,
     };
   }
 
@@ -260,7 +260,7 @@ function buildDecisionTreeC45(
       quality: _quality,
       matchedCount: _positiveCounter,
       notMatchedCount: _negativeCounter,
-      trainingSet2: trainingSet.map(x => x[categoryAttr]),
+      trainingSet2: trainingSet,
     };
   }
 
diff --git a/public/algorithms/tsp-tree.js b/public/algorithms/tsp-tree.js
index b047393..6e1bb08 100644
--- a/public/algorithms/tsp-tree.js
+++ b/public/algorithms/tsp-tree.js
@@ -55,7 +55,7 @@ function buildDecisionTreeTSP(
       quality: _quality,
       matchedCount: _positiveCounter,
       notMatchedCount: _negativeCounter,
-      trainingSet2: trainingSet.map(x => x[categoryAttr]),
+      trainingSet2: trainingSet,
     };
   }
   var attributes = builder.allAttributes.filter(function (el) {
@@ -219,7 +219,7 @@ function buildDecisionTreeTSP(
       quality: _quality,
       matchedCount: _positiveCounter,
       notMatchedCount: _negativeCounter,
-      trainingSet2: trainingSet.map(x => x[categoryAttr]),
+      trainingSet2: trainingSet,
     };
   }
   // sprawdzic
@@ -244,7 +244,7 @@ function buildDecisionTreeTSP(
       quality: _quality,
       matchedCount: _positiveCounter,
       notMatchedCount: _negativeCounter,
-      trainingSet2: trainingSet.map(x => x[categoryAttr]),
+      trainingSet2: trainingSet,
     };
   }
 
diff --git a/public/algorithms/tsp-weight-tree.js b/public/algorithms/tsp-weight-tree.js
index 728052c..8d49e22 100644
--- a/public/algorithms/tsp-weight-tree.js
+++ b/public/algorithms/tsp-weight-tree.js
@@ -17,7 +17,7 @@
  * @param {boolean} isChanged
  */
 //TSP-weight
-export function buildDecisionTreeTSPW(
+function buildDecisionTreeTSPW(
   _builder,
   isChanged = false,
   changedAttribute1 = null,
@@ -52,7 +52,7 @@ export function buildDecisionTreeTSPW(
       quality: _quality,
       matchedCount: _positiveCounter,
       notMatchedCount: _negativeCounter,
-      trainingSet2: trainingSet.map(x => x[categoryAttr]),
+      trainingSet2: trainingSet,
     };
   }
   var attributes = builder.allAttributes.filter(function (el) {
@@ -217,7 +217,7 @@ export function buildDecisionTreeTSPW(
       quality: _quality,
       matchedCount: _positiveCounter,
       notMatchedCount: _negativeCounter,
-      trainingSet2: trainingSet.map(x => x[categoryAttr]),
+      trainingSet2: trainingSet,
     };
   }
   // sprawdzic
@@ -242,7 +242,7 @@ export function buildDecisionTreeTSPW(
       quality: _quality,
       matchedCount: _positiveCounter,
       notMatchedCount: _negativeCounter,
-      trainingSet2: trainingSet.map(x => x[categoryAttr]),
+      trainingSet2: trainingSet,
     };
   }
 
diff --git a/src/components/Node/Joint.jsx b/src/components/Node/Joint.jsx
index 4961af2..16da378 100644
--- a/src/components/Node/Joint.jsx
+++ b/src/components/Node/Joint.jsx
@@ -11,11 +11,12 @@ import {
   ModalOverlay,
   useDisclosure,
 } from '@chakra-ui/react';
+import { CloseIcon } from '@chakra-ui/icons';
 import React, { useState } from 'react';
 import Configurator from './Configurator';
 import ModalPopup from './ModalPopup';
 
-function Joint({ children, attr2, predicateName, pivot, match, notMatch, onChange, nodeSet }) {
+function Joint({ children, attr2, predicateName, pivot, weight, requestFoldToLeaf, onChange, nodeSet }) {
   const { isOpen, onOpen, onClose } = useDisclosure();
   const [size, setSize] = useState('lg');
 
@@ -26,6 +27,9 @@ function Joint({ children, attr2, predicateName, pivot, match, notMatch, onChang
   const buildNewNode = () => {
     onChange();
   };
+
+  const foldToLeaf = () => requestFoldToLeaf();
+
   return (
     <Box>
       <Badge
@@ -35,9 +39,13 @@ function Joint({ children, attr2, predicateName, pivot, match, notMatch, onChang
         colorScheme="teal"
         onClick={handleOpenModalClick}
         className={'badge'}
+        marginRight={3}
       >
-        {attr2} <b>{predicateName}</b> {pivot}
+        {attr2} <b>{predicateName}</b> {weight} {pivot}
       </Badge>
+      <Button size="xs" rightIcon={<CloseIcon />} onClick={foldToLeaf}>
+        Fold
+      </Button>
       <ModalPopup
         isOpen={isOpen}
         nodeSet={nodeSet}
@@ -47,6 +55,7 @@ function Joint({ children, attr2, predicateName, pivot, match, notMatch, onChang
         onChange={onChange}
         onClose={onClose}
         onOpen={onOpen}
+        weight={weight}
       />
       {/* <Modal onClose={onClose} size={size} isOpen={isOpen}>
         <ModalOverlay />
diff --git a/src/components/Node/Leaf.jsx b/src/components/Node/Leaf.jsx
index d077d87..5616849 100644
--- a/src/components/Node/Leaf.jsx
+++ b/src/components/Node/Leaf.jsx
@@ -1,7 +1,8 @@
-import { Box } from '@chakra-ui/react';
+import { Box, Button, Menu, MenuButton, MenuItem, MenuList } from '@chakra-ui/react';
 import React from 'react';
+import { ChevronDownIcon, DownloadIcon } from '@chakra-ui/icons';
 
-function Leaf({ category, matchedCount, notMatchedCount, quality }) {
+function Leaf({ category, matchedCount, notMatchedCount, quality, requestLeafUnfold }) {
   return (
     <Box
       d="flex"
@@ -36,6 +37,16 @@ function Leaf({ category, matchedCount, notMatchedCount, quality }) {
       <Box mt="1" ml="2" fontWeight="semibold" as="h4" lineHeight="tight" isTruncated>
         {quality}%
       </Box>
+      <Menu closeOnSelect closeOnBlur>
+        <MenuButton fontSize="sm" w={20} h={6} as={Button} rightIcon={<ChevronDownIcon />}>
+          Unfold
+        </MenuButton>
+        <MenuList>
+          <MenuItem onClick={() => requestLeafUnfold('c45')}>C 4.5</MenuItem>
+          <MenuItem onClick={() => requestLeafUnfold('tsp')}>TSP</MenuItem>
+          <MenuItem onClick={() => requestLeafUnfold('tspw')}>TSP Weight</MenuItem>
+        </MenuList>
+      </Menu>
     </Box>
   );
 }
diff --git a/src/components/Node/ModalPopup.jsx b/src/components/Node/ModalPopup.jsx
index 9ebf914..0aa8888 100644
--- a/src/components/Node/ModalPopup.jsx
+++ b/src/components/Node/ModalPopup.jsx
@@ -11,7 +11,7 @@ import {
 } from '@chakra-ui/react';
 import Configurator from './Configurator';
 
-function ModalPopup({ attr2, predicateName, pivot, isOpen, nodeSet, onOpen, onChange, onClose }) {
+function ModalPopup({ attr2, predicateName, pivot, weight, isOpen, nodeSet, onOpen, onChange, onClose }) {
   const handleOnChange = value => {
     onClose();
     onChange(value);
@@ -32,7 +32,7 @@ function ModalPopup({ attr2, predicateName, pivot, isOpen, nodeSet, onOpen, onCh
               {x.attr1001} {x[attr2]}-{x[pivot]} {x[attr2] < x[pivot] ? 'Match' : 'NotMatch'}
             </div>
           ))} */}
-          <Configurator onChange={handleOnChange} attribute={attr2} pivot={pivot} />
+          <Configurator onChange={handleOnChange} attribute={attr2} pivot={pivot} weight={weight} />
         </ModalBody>
         <ModalFooter>
           <Button onClick={onClose}>Close</Button>
diff --git a/src/components/Node/index.jsx b/src/components/Node/index.jsx
index 22346ff..e4113ef 100644
--- a/src/components/Node/index.jsx
+++ b/src/components/Node/index.jsx
@@ -1,7 +1,7 @@
 import { Spinner } from '@chakra-ui/react';
 import React, { useEffect, useMemo, useState } from 'react';
 import { useBuilderConfigContext } from '../../contexts/BuilderConfigContext';
-import { executeAlgorithm } from '../../utils/algorithm-executor';
+import { executeAlgorithm, mostFrequentValue } from '../../utils/algorithm-executor';
 //import { addNode } from "./utils";
 
 import Joint from './Joint';
@@ -25,9 +25,13 @@ const Node = props => {
     predicateName,
     pivot,
     nodeSet,
+    weight,
   } = node;
 
   const onNodeClicked = e => {
+    if (!e.target.classList.contains('node')) {
+      return;
+    }
     //console.log(e);
     e.stopPropagation();
     console.log('Node clicked', node);
@@ -85,6 +89,29 @@ const Node = props => {
     props.requestChildChange(targetNode);
   };
 
+  const foldJointToLeaf = () => {
+    const foldResult = mostFrequentValue(nodeSet, builderConfig.categoryAttr);
+    setNode(foldResult);
+    props.requestChildChange(foldResult);
+  };
+
+  const unfoldLeaf = algorithm => {
+    setLoading(true);
+    executeAlgorithm({
+      ...builderConfig,
+      trainingSet: node.trainingSet2,
+      algorithm,
+    })
+      .then(value => {
+        setNode(value);
+        props.requestChildChange(value);
+      })
+      .catch(e => console.error(e))
+      .finally(() => {
+        setLoading(false);
+      });
+  };
+
   if (loading) {
     return <Spinner size="xl" />;
   }
@@ -97,6 +124,7 @@ const Node = props => {
           matchedCount={matchedCount}
           notMatchedCount={notMatchedCount}
           quality={quality}
+          requestLeafUnfold={unfoldLeaf}
         />
       ) : (
         <Joint
@@ -106,7 +134,9 @@ const Node = props => {
           match={match}
           notMatch={notMatch}
           onChange={onChange}
+          requestFoldToLeaf={foldJointToLeaf}
           nodeSet={nodeSet}
+          weight={weight}
         >
           <Node node={match} onChange={onChange} requestChildChange={requestChildChangeIfMatchIs(true)} />
           <Node node={notMatch} onChange={onChange} requestChildChange={requestChildChangeIfMatchIs(false)} />
diff --git a/src/utils/algorithm-executor.js b/src/utils/algorithm-executor.js
index 332e0d1..0babc53 100644
--- a/src/utils/algorithm-executor.js
+++ b/src/utils/algorithm-executor.js
@@ -17,3 +17,47 @@ export function executeAlgorithm(options, changeOptions = {}) {
     worker.postMessage({ _builder: { ...options }, ...changeOptions });
   });
 }
+
+function countUniqueValues(items, attr) {
+  var counter = {};
+
+  // detecting different values of attribute
+  for (var i = items.length - 1; i >= 0; i--) {
+    // items[i][attr] - value of attribute
+    counter[items[i][attr]] = 0;
+  }
+
+  // counting number of occurrences of each of values
+  // of attribute
+  for (var j = items.length - 1; j >= 0; j--) {
+    counter[items[j][attr]] += 1;
+  }
+
+  return counter;
+}
+
+export function mostFrequentValue(items, attr) {
+  const counter = countUniqueValues(items, attr);
+
+  var mostFrequentCount = 0;
+  var mostFrequentValue;
+
+  for (var value in counter) {
+    if (counter[value] > mostFrequentCount) {
+      mostFrequentCount = counter[value];
+      mostFrequentValue = value;
+    }
+  }
+
+  const _positiveCounter = items.filter(element => element[attr] === mostFrequentValue).length;
+  const _negativeCounter = items.length - _positiveCounter;
+  const _quality = 100 * (_positiveCounter / items.length);
+
+  return {
+    category: mostFrequentValue,
+    quality: _quality.toFixed(2),
+    matchedCount: _positiveCounter,
+    notMatchedCount: _negativeCounter,
+    trainingSet2: items,
+  };
+}