The Text pane forms the right side the right side of any document window tab, i.e. everything to the right of the vertical spitter bar. By default the pane only shows the Text tab of the text pane (more on the content of the Text tab).
In fact, the Text pane has three tabs: Text, Preview and HTML, with the latter two hidden by default, as mentioned above.
As many Tinderbox projects do not need to export HTML (or any kind of marked-up text) at all, the selectors for these three tabs are hidden by default. To reveal these tab controls Use the Window menu ▸ Shown/Hide Text Pane Selector will toggle the visibility of all sub-tabs.
From v9.5.0, the Text Pane Selector is now visible unless the user hides it; previously, it was hidden until you showed it. This change reflects increasing use of the preview tab as a presentation mode whereas originally is was designed for checking the render before HTML export, and thus on no need for those who do not use HTML export.
When first opening the document, if the text pane selector is initially hidden, hiding it is deferred slightly to allow seeing it sliding away, helping to confirm that it is deliberately hidden (and suggesting that there is a way to recover it).
Printing is possible from all 3 sub-panes (the Preview pane from v9.5.0).
In all three tabs, the text pane's title offers a tooltip containing the path of the note.
The sub-tabs are: