diff --git a/src/vs/base/browser/ui/tree/abstractTree.ts b/src/vs/base/browser/ui/tree/abstractTree.ts
index b41038a342d..5b7385865c4 100644
--- a/src/vs/base/browser/ui/tree/abstractTree.ts
+++ b/src/vs/base/browser/ui/tree/abstractTree.ts
@@ -233,16 +233,16 @@ export abstract class AbstractTree<T, TFilterData, TRef> implements IDisposable
 
 	// Tree navigation
 
-	getParentElement(ref: TRef | null = null): T | null {
-		return this.model.getParentElement(ref);
+	getParentElement(location: TRef | null = null): T | null {
+		return this.model.getParentElement(location);
 	}
 
-	getFirstElementChild(ref: TRef | null = null): T | null {
-		return this.model.getFirstElementChild(ref);
+	getFirstElementChild(location: TRef | null = null): T | null {
+		return this.model.getFirstChildElement(location);
 	}
 
-	getLastElementAncestor(ref: TRef | null = null): T | null {
-		return this.model.getLastElementAncestor(ref);
+	getLastElementAncestor(location: TRef | null = null): T | null {
+		return this.model.getLastAncestorElement(location);
 	}
 
 	// Tree
@@ -259,20 +259,20 @@ export abstract class AbstractTree<T, TFilterData, TRef> implements IDisposable
 		return this.model.setCollapsed(location, false);
 	}
 
-	toggleCollapsed(ref: TRef): void {
-		this.model.toggleCollapsed(ref);
+	toggleCollapsed(location: TRef): void {
+		this.model.toggleCollapsed(location);
 	}
 
 	collapseAll(): void {
 		this.model.collapseAll();
 	}
 
-	isCollapsed(ref: TRef): boolean {
-		return this.model.isCollapsed(ref);
+	isCollapsed(location: TRef): boolean {
+		return this.model.isCollapsed(location);
 	}
 
-	isExpanded(ref: TRef): boolean {
-		return !this.isCollapsed(ref);
+	isExpanded(location: TRef): boolean {
+		return !this.isCollapsed(location);
 	}
 
 	refilter(): void {
diff --git a/src/vs/base/browser/ui/tree/indexTreeModel.ts b/src/vs/base/browser/ui/tree/indexTreeModel.ts
index ccda698af3b..d0b64b0d19c 100644
--- a/src/vs/base/browser/ui/tree/indexTreeModel.ts
+++ b/src/vs/base/browser/ui/tree/indexTreeModel.ts
@@ -130,7 +130,7 @@ export class IndexTreeModel<T, TFilterData = void> implements ITreeModel<T, TFil
 	}
 
 	collapseAll(): void {
-		const queue = [...this.root.children]; // TODO@joao use a linked list
+		const queue = [...this.root.children];
 		let listIndex = 0;
 
 		this.eventBufferer.bufferEvents(() => {
@@ -428,7 +428,7 @@ export class IndexTreeModel<T, TFilterData = void> implements ITreeModel<T, TFil
 		return node === this.root ? null : node.element;
 	}
 
-	getFirstElementChild(location: number[]): T | null {
+	getFirstChildElement(location: number[]): T | null {
 		const node = this.getTreeNode(location);
 
 		if (node.children.length === 0) {
@@ -438,7 +438,7 @@ export class IndexTreeModel<T, TFilterData = void> implements ITreeModel<T, TFil
 		return node.children[0].element;
 	}
 
-	getLastElementAncestor(location: number[]): T | null {
+	getLastAncestorElement(location: number[]): T | null {
 		const node = this.getTreeNode(location);
 
 		if (node.children.length === 0) {
diff --git a/src/vs/base/browser/ui/tree/objectTreeModel.ts b/src/vs/base/browser/ui/tree/objectTreeModel.ts
index a465e82742a..54d40157a64 100644
--- a/src/vs/base/browser/ui/tree/objectTreeModel.ts
+++ b/src/vs/base/browser/ui/tree/objectTreeModel.ts
@@ -52,14 +52,14 @@ export class ObjectTreeModel<T extends NonNullable<any>, TFilterData = void> imp
 		return this.model.getParentElement(location);
 	}
 
-	getFirstElementChild(ref: T | null = null): T | null {
+	getFirstChildElement(ref: T | null = null): T | null {
 		const location = this.getElementLocation(ref);
-		return this.model.getFirstElementChild(location);
+		return this.model.getFirstChildElement(location);
 	}
 
-	getLastElementAncestor(ref: T | null = null): T | null {
+	getLastAncestorElement(ref: T | null = null): T | null {
 		const location = this.getElementLocation(ref);
-		return this.model.getLastElementAncestor(location);
+		return this.model.getLastAncestorElement(location);
 	}
 
 	getListIndex(element: T): number {
diff --git a/src/vs/base/browser/ui/tree/tree.ts b/src/vs/base/browser/ui/tree/tree.ts
index 566ba1343b7..ce18673a021 100644
--- a/src/vs/base/browser/ui/tree/tree.ts
+++ b/src/vs/base/browser/ui/tree/tree.ts
@@ -51,20 +51,21 @@ export interface ITreeModel<T, TFilterData, TRef> {
 	readonly onDidChangeCollapseState: Event<ITreeNode<T, TFilterData>>;
 	readonly onDidChangeRenderNodeCount: Event<ITreeNode<T, TFilterData>>;
 
-	getListIndex(ref: TRef): number;
-	setCollapsed(ref: TRef, collapsed: boolean): boolean;
-	toggleCollapsed(ref: TRef): void;
-	collapseAll(): void;
-	isCollapsed(ref: TRef): boolean;
-	refilter(): void;
-
+	getListIndex(location: TRef): number;
 	getNode(location?: TRef): ITreeNode<T, any>;
 	getNodeLocation(node: ITreeNode<T, any>): TRef;
 	getParentNodeLocation(location: TRef): TRef | null;
 
 	getParentElement(location: TRef): T | null;
-	getFirstElementChild(location: TRef): T | null;
-	getLastElementAncestor(location: TRef): T | null;
+	getFirstChildElement(location: TRef): T | null;
+	getLastAncestorElement(location: TRef): T | null;
+
+	isCollapsed(location: TRef): boolean;
+	setCollapsed(location: TRef, collapsed: boolean): boolean;
+	toggleCollapsed(location: TRef): void;
+	collapseAll(): void;
+
+	refilter(): void;
 }
 
 export interface ITreeRenderer<T, TFilterData, TTemplateData> extends IListRenderer<ITreeNode<T, TFilterData>, TTemplateData> {