fieldgroup and empty value in child field

with pleasure

PS:

Just fyi, I found out something:

Again, the problem-abstract is:
In php, when reading fieldgroups' data (incl. value, thumbs_src, display_arr, etc.),
images "sometimes" land in the wrong indexes:

EXAMPLE:
User intends to build a slideshow via backend-form;
backend-form shows fieldgroup;
fieldgroup has fieldgroup-elements with text and image fields;
only last element's image is filled by user.

EXPECTED: image in php (field's thumbs_src) shows in last array element.
OBSERVED: image in php (field' thumbs_src) shows in seemingly random (e.g. first) array element.

SOLUTION:
Solutions is to load (aka. FlexicontentFields::getFieldDisplay()) the fields in the right order. The right order is: fieldgroup"-fields last

This is reproducable here, and was not intuitive for me until now. Maybe i missed some docs though