diff --git a/packages/mindplot/src/components/DragTopic.ts b/packages/mindplot/src/components/DragTopic.ts
index f099f54b..32aee308 100644
--- a/packages/mindplot/src/components/DragTopic.ts
+++ b/packages/mindplot/src/components/DragTopic.ts
@@ -67,7 +67,7 @@ class DragTopic {
     const cy = Math.ceil(y - size.height / 2);
     this._elem2d.setPosition(cx, cy);
 
-    // In case is not free, pivot must be draw ...
+    // In case is not free, pivot must be drawn ...
     if (this.isConnected()) {
       const parent = this.getConnectedToTopic();
       const predict = this._layoutManager.predict(
diff --git a/packages/mindplot/src/components/Topic.ts b/packages/mindplot/src/components/Topic.ts
index c790902c..5eef5d9c 100644
--- a/packages/mindplot/src/components/Topic.ts
+++ b/packages/mindplot/src/components/Topic.ts
@@ -1044,7 +1044,6 @@ abstract class Topic extends NodeGraph {
         const connector = targetTopic.getShrinkConnector();
         if (connector) {
           connector.setVisibility(false);
-          targetTopic.setChildrenShrunken(true);
         }
       }
 
diff --git a/packages/mindplot/src/components/layout/AbstractBasicSorter.ts b/packages/mindplot/src/components/layout/AbstractBasicSorter.ts
index 8ccce86d..52a2116b 100644
--- a/packages/mindplot/src/components/layout/AbstractBasicSorter.ts
+++ b/packages/mindplot/src/components/layout/AbstractBasicSorter.ts
@@ -24,21 +24,25 @@ import RootedTreeSet from './RootedTreeSet';
 abstract class AbstractBasicSorter extends ChildrenSorterStrategy {
   private INTERNODE_VERTICAL_PADDING = 5;
 
-  computeChildrenIdByHeights(treeSet: RootedTreeSet, node: Node) {
-    const result = {};
+  computeChildrenIdByHeights(treeSet: RootedTreeSet, node: Node): Map<number, number> {
+    const result = new Map<number, number>();
     this._computeChildrenHeight(treeSet, node, result);
     return result;
   }
 
-  protected _getVerticalPadding() {
+  getVerticalPadding(): number {
     return this.INTERNODE_VERTICAL_PADDING;
   }
 
-  protected _computeChildrenHeight(treeSet: RootedTreeSet, node: Node, heightCache?) {
+  _computeChildrenHeight(
+    treeSet: RootedTreeSet,
+    node: Node,
+    heightCache?: Map<number, number>,
+  ): number {
     // 2* Top and down padding;
-    const height = node.getSize().height + this._getVerticalPadding() * 2;
+    const height = node.getSize().height + this.getVerticalPadding() * 2;
 
-    let result;
+    let result: number;
     const children = treeSet.getChildren(node);
     if (children.length === 0 || node.areChildrenShrunken()) {
       result = height;
@@ -53,8 +57,7 @@ abstract class AbstractBasicSorter extends ChildrenSorterStrategy {
     }
 
     if (heightCache) {
-      // eslint-disable-next-line no-param-reassign
-      heightCache[node.getId()] = result;
+      heightCache.set(node.getId(), result);
     }
 
     return result;
diff --git a/packages/mindplot/src/components/layout/BalancedSorter.ts b/packages/mindplot/src/components/layout/BalancedSorter.ts
index f2ec375d..cf649ba0 100644
--- a/packages/mindplot/src/components/layout/BalancedSorter.ts
+++ b/packages/mindplot/src/components/layout/BalancedSorter.ts
@@ -233,13 +233,13 @@ class BalancedSorter extends AbstractBasicSorter {
     return 'Balanced Sorter';
   }
 
-  protected _getChildrenForOrder(parent: Node, graph: RootedTreeSet, order: number): Node[] {
+  _getChildrenForOrder(parent: Node, graph: RootedTreeSet, order: number): Node[] {
     return this._getSortedChildren(graph, parent).filter(
       (child) => child.getOrder() % 2 === order % 2,
     );
   }
 
-  protected _getVerticalPadding(): number {
+  getVerticalPadding(): number {
     return BalancedSorter.INTERNODE_VERTICAL_PADDING;
   }
 }
diff --git a/packages/mindplot/src/components/layout/ChildrenSorterStrategy.ts b/packages/mindplot/src/components/layout/ChildrenSorterStrategy.ts
index 3b0b852f..0806d30e 100644
--- a/packages/mindplot/src/components/layout/ChildrenSorterStrategy.ts
+++ b/packages/mindplot/src/components/layout/ChildrenSorterStrategy.ts
@@ -20,7 +20,7 @@ import Node from './Node';
 import PositionType from '../PositionType';
 
 abstract class ChildrenSorterStrategy {
-  abstract computeChildrenIdByHeights(treeSet: RootedTreeSet, node: Node): void;
+  abstract computeChildrenIdByHeights(treeSet: RootedTreeSet, node: Node): Map<number, number>;
 
   abstract computeOffsets(treeSet: RootedTreeSet, node: Node): void;
 
@@ -33,13 +33,15 @@ abstract class ChildrenSorterStrategy {
     parent: Node,
     node: Node | null,
     position: PositionType | null,
-  );
+  ): void;
 
   abstract verify(treeSet: RootedTreeSet, node: Node): void;
 
   abstract getChildDirection(treeSet: RootedTreeSet, node: Node): 1 | -1;
 
   abstract toString(): string;
+
+  abstract getVerticalPadding(): number;
 }
 
 export default ChildrenSorterStrategy;
diff --git a/packages/mindplot/src/components/layout/Node.ts b/packages/mindplot/src/components/layout/Node.ts
index c2f8c4ee..af05655d 100644
--- a/packages/mindplot/src/components/layout/Node.ts
+++ b/packages/mindplot/src/components/layout/Node.ts
@@ -33,6 +33,10 @@ class Node {
   // eslint-disable-next-line no-use-before-define
   _children!: Node[];
 
+  _branchHeight: number;
+
+  _heightChanged: boolean;
+
   constructor(id: number, size: SizeType, position: PositionType, sorter: ChildrenSorterStrategy) {
     $assert(typeof id === 'number' && Number.isFinite(id), 'id can not be null');
     this._id = id;
@@ -42,6 +46,8 @@ class Node {
     this.setSize(size);
     this.setPosition(position);
     this.setShrunken(false);
+    this._branchHeight = -1;
+    this._heightChanged = false;
   }
 
   /** */
diff --git a/packages/mindplot/src/components/layout/OriginalLayout.js b/packages/mindplot/src/components/layout/OriginalLayout.ts
similarity index 77%
rename from packages/mindplot/src/components/layout/OriginalLayout.js
rename to packages/mindplot/src/components/layout/OriginalLayout.ts
index 61df0be7..4c492cc7 100644
--- a/packages/mindplot/src/components/layout/OriginalLayout.js
+++ b/packages/mindplot/src/components/layout/OriginalLayout.ts
@@ -19,27 +19,26 @@ import { $assert, $defined } from '@wisemapping/core-js';
 import Node from './Node';
 import SymmetricSorter from './SymmetricSorter';
 import BalancedSorter from './BalancedSorter';
+import RootedTreeSet from './RootedTreeSet';
+import SizeType from '../SizeType';
+import PositionType from '../PositionType';
+import ChildrenSorterStrategy from './ChildrenSorterStrategy';
 
 class OriginalLayout {
-  constructor(treeSet) {
+  private _treeSet: RootedTreeSet;
+
+  constructor(treeSet: RootedTreeSet) {
     this._treeSet = treeSet;
   }
 
-  /** */
-  // eslint-disable-next-line class-methods-use-this
-  createNode(id, size, position, type) {
+  createNode(id: number, size: SizeType, position: PositionType, type: string): Node {
     $assert($defined(id), 'id can not be null');
-    $assert(size, 'size can not be null');
-    $assert(position, 'position can not be null');
-    $assert(type, 'type can not be null');
-
-    const strategy =
+    const strategy: ChildrenSorterStrategy =
       type === 'root' ? OriginalLayout.BALANCED_SORTER : OriginalLayout.SYMMETRIC_SORTER;
     return new Node(id, size, position, strategy);
   }
 
-  /** */
-  connectNode(parentId, childId, order) {
+  connectNode(parentId: number, childId: number, order: number): void {
     const parent = this._treeSet.find(parentId);
     const child = this._treeSet.find(childId);
 
@@ -54,11 +53,12 @@ class OriginalLayout {
     sorter.verify(this._treeSet, parent);
   }
 
-  /** */
-  disconnectNode(nodeId) {
+  disconnectNode(nodeId: number): void {
     const node = this._treeSet.find(nodeId);
     const parent = this._treeSet.getParent(node);
-    $assert(parent, 'Node already disconnected');
+    if (!parent) {
+      throw new Error('Node already disconnected');
+    }
 
     // Make it fixed
     node.setFree(false);
@@ -75,21 +75,18 @@ class OriginalLayout {
     parent.getSorter().verify(this._treeSet, parent);
   }
 
-  /** */
-  layout() {
+  layout(): void {
     const roots = this._treeSet.getTreeRoots();
     roots.forEach((node) => {
       // Calculate all node heights ...
       const sorter = node.getSorter();
-
       const heightById = sorter.computeChildrenIdByHeights(this._treeSet, node);
       this._layoutChildren(node, heightById);
-
       this._fixOverlapping(node, heightById);
     });
   }
 
-  _layoutChildren(node, heightById) {
+  private _layoutChildren(node: Node, heightById: Map<number, number>): void {
     const nodeId = node.getId();
     const children = this._treeSet.getChildren(node);
     const parent = this._treeSet.getParent(node);
@@ -98,9 +95,9 @@ class OriginalLayout {
 
     // If ether any of the nodes has been changed of position or the height of the children is not
     // the same, children nodes must be repositioned ....
-    const newBranchHeight = heightById[nodeId];
+    const newBranchHeight = heightById.get(nodeId)!;
 
-    const parentHeightChanged = $defined(parent) ? parent._heightChanged : false;
+    const parentHeightChanged = parent ? parent._heightChanged : false;
     const heightChanged = node._branchHeight !== newBranchHeight;
     // eslint-disable-next-line no-param-reassign
     node._heightChanged = heightChanged || parentHeightChanged;
@@ -141,7 +138,6 @@ class OriginalLayout {
         me._treeSet.updateBranchPosition(child, newPos);
       });
 
-      // eslint-disable-next-line no-param-reassign
       node._branchHeight = newBranchHeight;
     }
 
@@ -151,7 +147,7 @@ class OriginalLayout {
     });
   }
 
-  _calculateAlignOffset(node, child, heightById) {
+  private _calculateAlignOffset(node: Node, child: Node, heightById: Map<number, number>): number {
     if (child.isFree()) {
       return 0;
     }
@@ -167,8 +163,8 @@ class OriginalLayout {
     ) {
       if (this._treeSet.hasSinglePathToSingleLeaf(child)) {
         offset =
-          heightById[child.getId()] / 2 -
-          (childHeight + child.getSorter()._getVerticalPadding() * 2) / 2;
+          heightById.get(child.getId())! / 2 -
+          (childHeight + child.getSorter().getVerticalPadding() * 2) / 2;
       } else {
         offset = this._treeSet.isLeaf(child) ? 0 : -(childHeight - nodeHeight) / 2;
       }
@@ -189,13 +185,14 @@ class OriginalLayout {
     return offset;
   }
 
-  static _branchIsTaller(node, heightById) {
+  static _branchIsTaller(node: Node, heightById: Map<number, number>): boolean {
     return (
-      heightById[node.getId()] > node.getSize().height + node.getSorter()._getVerticalPadding() * 2
+      heightById.get(node.getId())! >
+      node.getSize().height + node.getSorter().getVerticalPadding() * 2
     );
   }
 
-  _fixOverlapping(node, heightById) {
+  private _fixOverlapping(node: Node, heightById: Map<number, number>): void {
     const children = this._treeSet.getChildren(node);
 
     if (node.isFree()) {
@@ -206,7 +203,7 @@ class OriginalLayout {
     });
   }
 
-  _shiftBranches(node, heightById) {
+  _shiftBranches(node: Node, heightById: Map<number, number>): void {
     const shiftedBranches = [node];
 
     const siblingsToShift = this._treeSet.getSiblingsInVerticalDirection(
@@ -238,28 +235,22 @@ class OriginalLayout {
     });
   }
 
-  static _branchesOverlap(branchA, branchB, heightById) {
+  static _branchesOverlap(branchA: Node, branchB: Node, heightById: Map<number, number>): boolean {
     // a branch doesn't really overlap with itself
     if (branchA === branchB) {
       return false;
     }
 
-    const topA = branchA.getPosition().y - heightById[branchA.getId()] / 2;
-    const bottomA = branchA.getPosition().y + heightById[branchA.getId()] / 2;
-    const topB = branchB.getPosition().y - heightById[branchB.getId()] / 2;
-    const bottomB = branchB.getPosition().y + heightById[branchB.getId()] / 2;
+    const topA = branchA.getPosition().y - heightById.get(branchA.getId())! / 2;
+    const bottomA = branchA.getPosition().y + heightById.get(branchA.getId())! / 2;
+    const topB = branchB.getPosition().y - heightById.get(branchB.getId())! / 2;
+    const bottomB = branchB.getPosition().y + heightById.get(branchB.getId())! / 2;
 
     return !(topA >= bottomB || bottomA <= topB);
   }
+
+  static SYMMETRIC_SORTER: ChildrenSorterStrategy = new SymmetricSorter();
+
+  static BALANCED_SORTER: ChildrenSorterStrategy = new BalancedSorter();
 }
-
-/**
- * @type {mindplot.layout.SymmetricSorter}
- */
-OriginalLayout.SYMMETRIC_SORTER = new SymmetricSorter();
-/**
- * @type {mindplot.layout.BalancedSorter}
- */
-OriginalLayout.BALANCED_SORTER = new BalancedSorter();
-
 export default OriginalLayout;
diff --git a/packages/mindplot/src/components/layout/SymmetricSorter.ts b/packages/mindplot/src/components/layout/SymmetricSorter.ts
index d6b03941..8473bcc7 100644
--- a/packages/mindplot/src/components/layout/SymmetricSorter.ts
+++ b/packages/mindplot/src/components/layout/SymmetricSorter.ts
@@ -25,7 +25,13 @@ class SymmetricSorter extends AbstractBasicSorter {
   /**
    * Predict the order and position of a dragged node.
    */
-  predict(graph: RootedTreeSet, parent: Node, node: Node, position: PositionType, free?: boolean) {
+  predict(
+    graph: RootedTreeSet,
+    parent: Node,
+    node: Node,
+    position: PositionType,
+    free?: boolean,
+  ): [number, PositionType] {
     const self = this;
     const rootNode = graph.getRootNode(parent);
 
@@ -97,7 +103,7 @@ class SymmetricSorter extends AbstractBasicSorter {
     const last = parentChildren[parentChildren.length - 1];
     for (let i = 0; i < parentChildren.length; i++) {
       const parentChild = parentChildren[i];
-      const nodeAfter = i + 1 === parentChildren.length ? null : parentChildren[i + 1];
+      const nodeAfter = parentChildren[i + 1];
 
       // Fit at the bottom
       if (!nodeAfter && position.y > parentChild.getPosition().y) {
@@ -291,7 +297,7 @@ class SymmetricSorter extends AbstractBasicSorter {
     return 'Symmetric Sorter';
   }
 
-  protected _getVerticalPadding() {
+  getVerticalPadding() {
     return SymmetricSorter.INTERNODE_VERTICAL_PADDING;
   }