Fixing Theme Issues with WordPress 4.8 Media Widgets

WordPress 4.8 has just been released and, whilst not a ground breaking update, it includes some nice features that make WordPress more pleasant to use. One of the main areas focused on is some new widgets. There haven’t been any new core WordPress widgets added in years, and these ones are very welcome. The new widgets are an image widget, a video widget, and an audio widget. In addition the text widget now makes use of TinyMCE to add some extra control for users who don’t know HTML.
Problems and Solutions
Shortly after release I was alerted by the team at wordpress.com that a few of my themes didn’t play nicely with the new widgets. The issue is with ‘hidden’ sidebars. By this, I mean sidebars that start off hidden and then appear when a button is clicked. Any overlay or modal sidebars.
The problem is that when something is hidden javascript doesn’t know how big it is – and so positioning and sizing of elements can be (very) wrong. Videos in particular will probably be the wrong size, but the audio elements are also likely to have controls in the wrong place.
I then spent a few hours last weekend fixing the problem – with a few more
The
Source: https://managewp.org/articles/15332/fixing-theme-issues-with-wordpress-4-8-media-widgets

source https://williechiu40.wordpress.com/2017/06/16/fixing-theme-issues-with-wordpress-4-8-media-widgets/