Toolbar in Tool Window

I would to add a toolbar to my toolwindow. I would like to obtain a toolbar, as it appears here: https://jetbrains.github.io/ui/controls/toolbar/ . This toolbar should contains buttons, combobox and other controls.

I first of all tried building an ActionToolBar, by creating a group of actions and then building the toolbar from there. My problem with that is that I can only insert actions which are represented as buttons. I have no way to get a combobox or other controls. So the ActionToolBar does not seem to work for me.

I therefore tried to use a JToolBar instead. There I can add the controls I want but the look and feel is completely different:


So I am not sure what I am doing wrong.

Should I use an ActionToolBar? If so, how can I add controls different from buttons?
Should I use a JToolBar? If so, how can I obtain a toolbar that looks like the other toolbars within IntelliJ?
Should I use another solution? If so, do you jave any pointers?