I need to create a collapsible panel within another collapsible panel, with the nested panel requiring 3 columns in the heading. To achieve this, I am using a row element. However, when I add the row and container-fluid classes, the bottom border of the panel heading does not span across the entire width as expected. This issue can be seen below:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>test</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
</head>
<body style="padding-top:10px"></body>
<div class="panel-group">
<div class="panel panel-default">
<div class="panel-heading">
<h4 class="panel-title">
<a data-toggle="collapse" href="#collapseum1">This is a test</a>
</h4>
</div>
<div id="collapseum1" class="panel-collapse collapse">
<div class="panel-body">
<b>Description:</b> idk
<div class="panel panel-info container-fluid">
<div class="panel-heading row">
<div class="col-xs-1"><h4 class="panel-title"><a data-toggle="collapse" href="#collapseum1sub1"><b>Col1</b></a></h4></div>
<div class="col-xs-3 text-left">Col2</div>
<div class="col-xs-8 text-left">Col3</div>
</div>
<div id="collapseum1sub1" class="panel-collapse collapse">
<div class="panel-body">
<b>More stuff</b>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</body>
</html>