When some of the extra docker options were removed for the sake of simplicity, the option to remove the docker titlebars in the settings dropdown menu was also removed. Hiding the titlebars gives the dockers themselves a little bit of extra precious UI space and, more importantly, prevents accidential closing of some dockers. I quite liked it, and would like to see it return if at all possible.
Sorry, no, we're not going to do that. I miss it myself, but it just gives too much of a headache both in terms of user support for people who don't understand the feature and bugs on platforms where Qt's dockwidgets break when having a custom titlebar.
Ah, I see. Well, it was worth a shot. Thanks for the explanation.