src/vs/workbench/common/editor/editorGroupModel.ts/EditorGroupModel/doStick
class EditorGroupModel:	private doStick(editor: EditorInput, editorIndex: number): void {
		if (this.isSticky(editorIndex)) {
			return; // can only stick a non-sticky editor
		}

		// Pin editor
		this.pin(editor);

		// Move editor to be the last sticky editor
		const newEditorIndex = this.sticky + 1;
		this.moveEditor(editor, newEditorIndex);

		// Adjust sticky index
		this.sticky++;

		// Event
		const event: IGroupEditorChangeEvent = {
			kind: GroupModelChangeKind.EDITOR_STICKY,
			editor,
			editorIndex: newEditorIndex
		};
		this._onDidModelChange.fire(event);
	}