I had an issue with the plugin HiSlider not working within widgets on a WordPress installation, while working perfectly in a page or a post. The solution did not lie within plugin incompatibilities or PHP versions. It was a rather simple fix.
Navigate to your theme’s functions.php and add the following line of code:
add_filter('widget_text', 'do_shortcode');And that’s all it takes to enable shortcodes inside WordPress text widgets.