I'm trying to create a Dropdown Checkbox-list which is very similar to this example.
Please, pay attention to the "Tags" section of Search Articles
Additional to above features, I want to add an option "firstItemChecksAll" for each group i.e. select "All" for "Language, Platform, Technology, Audience..." etc.
p.s. I am aware of
but none of them fits what I want exactly so .....