X1 doesn't have a Maximise/Minimise icon or icons per se
If you've resized the height of a track manually, all that the new 'arrow' icon does is toggle between
Minimise and
Restore - there is
no Maximise option at all.
To maximise a track height to fit the window, you have to double click in an empty area of the pane.
However, this is not strictly a 'toggle' option - whether you double click to maximise from the minimised state or from the (manually set) restore state, when you double click again, the track always returns to the 'restore' height.
If you've not seen this behaviour, check it out - I'm guessing the replacement of the traditional minimise and maximise icons (which
do toggle as expected in S8.5) with just one icon was incorparated to save space?
In S8.5, the two separate icons work exactly as in other Windows programs:
Incidentally (and unless the forum software has changed the image dimensions

), my two screenshots also give an
exact comparision of the
minimum sizes of a track in X1 and in S8.5 that can show all the available information excluding the FX bin.
Again, try it yourselves - S8.5 seems to rearrange the information much more 'intelligently' than X1 when you resize the track pane - the FX bin disappears
much sooner in 8.5. This behaviour is consistent whether you resize the track pane vertically as well as horizontally.