// REMOVE P from shortcodes // https://gist.github.com/bitfade/4555047

WP REMOVE P from shortcodes.php

function the_content_filter($content) {
	// array of custom shortcodes requiring the fix 
	$block = join("|",array("iz_mehr","iz_col", "text_platzhalter"));
	// opening tag
	$rep = preg_replace("/(<p>)?\[($block)(\s[^\]]+)?\](<\/p>|<br \/>)?/","[$2$3]",$content);
		
	// closing tag
	$rep = preg_replace("/(<p>)?\[\/($block)](<\/p>|<br \/>)?/","[/$2]",$rep);
	return $rep;
}
add_filter("the_content", "the_content_filter");