Hi Limor,
I am afraid, Adding new buttons in the caption bar is not possible in our current docking manager. However already we have a feature request regarding the adding
Maximise and minimise button in the docking manager caption bar . I have once again notified the development team about it and we willl try our very best to address the same at the earliest.
You could also track the status of the feature request in the above link. We appreciate your patience and cooperation.
Thanks,
Vijay