Sorry for bothering you so much about my enquiry. I think we may have a bit different version of the software (I have downloaded it today) because under tabs (View, Options, Tracks, Clips, MIDI and Region FX) I don't have this blue indication of time. I have plus and multiple plus icons and then this combo box with All, Custom, Mix, FX, I/O, Track Control Manager options (you have different options on your screen shot).
So I have changed it to "All". What should I expect now? It didn't open for me any Track Header Widget (and C button still opens the same). I have also searched for "Track Header" in the documentation you mention but it didn't help me much.