Prevent BODY from scrolling when a modal is opened

Bootstrap’s modal automatically adds the class modal-open to the body when a modal dialog is shown and removes it when the dialog is hidden. You can therefore add the following to your CSS:

body.modal-open {
    overflow: hidden;
}

You could argue that the above code belongs to the Bootstrap CSS code base, but this is an easy fix to add it to your site.

A workaround would be to add the class to the body when the modal is about to be shown, and remove it when the modal is closed:

$("#myModal").on("show", function () {
  $("body").addClass("modal-open");
}).on("hidden", function () {
  $("body").removeClass("modal-open")
});

Note: to prevent the underlying page from jumping left/right when showing/hiding modals.

body {
    // STOP MOVING AROUND!
    overflow-x: hidden;
    overflow-y: scroll !important;
}

Flexbox – the same columns height

Make Bootstrap Columns All the Same Height

HTML:

<div class="container">
<div class="row is-flex">
<div class="col-sm-4">
<div class="box">
<h2>Title</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor.</p>
<a class="btn btn-primary" href="#">Link 1</a></div>
</div>
<div class="col-sm-4">
<div class="box">
<h2>Title</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor.</p>
<a class="btn btn-primary" href="#">Link 2</a></div>
</div>
<div class="col-sm-4">
<div class="box">
<h2>Ttitle</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt.</p>
<a class="btn btn-primary" href="#">Link 3</a></div>
</div>
</div>
</div>

CSS:

.row.is-flex {
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  flex-wrap: wrap;
}
.row.is-flex > [class*='col-'] {
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  flex-direction: column;
}

Solution 2 using table

.row {
    display: table;
}

[class*="col-"] {
    float: none;
    display: table-cell;
    vertical-align: top;
}

More Different Tricks on How to Make Bootstrap Columns All the Same Height: https://scotch.io/bar-talk/different-tricks-on-how-to-make-bootstrap-columns-all-the-same-height