Gallery field - shows empty tab even if there is no content

see topic.

Depending on the template ist shows:

list.php --> empty space

list-simple-one.php --> Notice: Undefined index: in com_cobalt/fields/gallery/tmpl/output/list-simple-one.php on line 23

full.php --> OK

full-galleria.io.php --> big black box

full-bootstrap-carousel.php --> shows left right navigation which disappears when hover over it

Only the full.php works as expected (regarding the display of content/display of tab).