I have a problem:
as you can see in the picture, the problem is, that the column doesn't take the full height. On the left side is what I got and on the right is what I want. Here is the source code which leads to the image on the left.
<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
</head>
<body>
<div>
<div class="row m-auto">
<div class="col-md-12 p-0">
<div>
<nav class="navbar navbar-expand-lg navbar-light bg-light">
<a class="navbar-brand" href="#">
Navbar w/ text
</a>
<button
class="navbar-toggler"
type="button"
data-toggle="collapse"
data-target="#navbarText"
aria-controls="navbarText"
aria-expanded="false"
aria-label="Toggle navigation"
>
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarText">
<ul class="navbar-nav mr-auto">
<li class="nav-item active">
<a class="nav-link" href="#">
Home <span class="sr-only">(current)</span>
</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">
Features
</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">
Pricing
</a>
</li>
</ul>
<span class="navbar-text">Navbar text with an inline element</span>
</div>
</nav>
</div>
<div class="container-fluid">
<div class="row">
<div class="col-md-4 bg-warning">
<!-- this is the left side -->
<div>
<div class="row m-1">
<div class="col-md-11">
Chats
</div>
<div class="col-md-1">
<i class="fas fa-plus-circle"></i>
</div>
</div>
<div class="row mb-2">
<div class="col-md-12">
<form class="form-inline" style={{ height: "0%", width: "100%", paddingLeft: "0", paddingRight: "0", paddingTop: "8px" }}>
<input class="form-control mr-sm-1" style={{ width: "80%" }} type="search" placeholder="Suchen" aria-label="Search" />
<button class="btn btn-outline-success my-2 my-sm-0" type="submit">Suchen</button>
</form>
</div>
</div>
<div class="row">
<div class="col-md-12">
<div class="list-group">
<div>
<a href="#" class="list-group-item list-group-item-action flex-column align-items-start" style={{marginTop: "7.5px", marginBottom: "7.5px"}}>
<div class="d-flex w-100 justify-content-between">
<h5 class="mb-1">List group item heading</h5>
<small>3 days ago</small>
</div>
<div class="row">
<div class="col-md-11">Donec id elit non mi porta...
</div>
<div class="col-md-1">
<span class="badge badge-primary badge-pill text-right">5</span>
</div>
</div>
</a>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="col-md-8 bg-primary">
<div>
<div class="row">
<div class="col-12 col-sm-12 col-md-12 col-lg-12 col-xl-12">
<div class="row">
<div class="col-12 col-sm-12 col-md-12 col-lg-12 col-xl-12 bg-success">
<div class="row">
<!-- it should be the full width but unfortunatelly a scrollbar appears because of this section right here... -->
<div class="col-2 col-sm-2 col-md-2 col-lg-2 col-xl-2">
<img src="..." class="image-head-chat" alt="Responsive image" />
</div>
<div class="col-8 col-sm-8 col-md-8 col-lg-8 col-xl-8">
Text
</div>
<div class="col-2 col-sm-2 col-md-2 col-lg-2 col-xl-2">
Icons
</div>
</div>
</div>
</div>
<div class="row">
<div class="col-12 col-sm-12 col-md-12 col-lg-12 col-xl-12 bg-success">
<!-- Should be in the middle and full screen (like the area where you and another person have a conversation-->
Message
</div>
</div>
<div class="row">
<!-- should be at the bottom of the Screen like in everyother Chat-->
<div class="col-12 col-sm-12 col-md-12 col-lg-12 col-xl-12 bg-success">
Text-Input and Button
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</body>
</html>
