It’s normal plugin behavior… Use shortcode instead of HTML.
Another solution is to change sanitize function inside of the plugin file itself, but than you will need to do it again and again after every update.
Sanitize function can be found inside mystickyelements.php file, just add elements u want inside array:
public function sanitize( $input )
{
array(
'a' => array(
'href' => array(),
'title' => array(),
'target' => array(),
'rel' => array()
),
'br' => array(),
'h1' => array(),
'h2' => array(),
'h3' => array(),
'h4' => array(),
'h5' => array(),
'h6' => array(),
' ' => array(),
'hr' => array(),
'p' => array(),
'em' => array(),
'strong' => array(),
'ul' => array(),
'ol' => array(),
'li' => array(),
'blockquote' => array(),
'iframe' => array(
'src' => array(),
'width' => array(),
'height' => array(),
'frameborder' => array(),
'allowfullscreen' => array(),
'scrolling' => array(),
'style' => array(),
'allowtransparency' => array()
),
'img' => array(
'src' => array(),
'alt' => array(),
'class' => array(),
'width' => array(),
'height' => array(),
'rel' => array()
),
'span' => array(
'style' => array(),
'class' => array()
)
)
);
