Transition bug in Firefox affects slidebars

[billynoah]

Filed a bug report here: https://bugzilla.mozilla.org/show_bug.cgi?id=1431893

If you check with Firefox version 57 (not sure how far back this goes but apparently it's fine on version 47) even the demo on your website is severely affected due to CSS transitions on the menubar items.

Workaround is to remove or override overflow properties from [off-canvas] and apply them to a wrapper <div> inside for your content:

[off-canvas] > .slidebar-scroll-container {
    height: 100%;
    overflow: hidden;
    overflow-auto: auto;
}