Hi Jozef,
With the shared code example I was able to get a bit more context of your use case and I was able to resolve your issue.
In your app.component.html file:

<div id="container">
    <smart-docking-layout #docking [layout]="layout"></smart-docking-layout>
    <smart-slider #slider></smart-slider>
    <smart-multiline-text-box #multilinetextbox></smart-multiline-text-box>

In your app.componen.css file:

body, html{
	width: 100%;
	height: 100%;
#container {
	width: 100%;
	height: 100%;
	position: absolute;
smart-slider {
	margin-top: 100px;
smart-docking-layout {
	width: 100%;
	height: 100%;

Let me know if that works for you!
Please, do not hesitate to contact us if you have any additional questions.
Best regards,
Yavor Dashev
Smart UI Team