Please click on the Tools tab and you would see the whole tools pane would drop down.
Or if you could share the screen shot how exactly it looks like, it would be great.
The tool tab AND the tool pane go away when I open up a portfolio to edit. It is present until I open a portfolio file to edit.
These tools apply to a specific PDF file. A portfolio file is just a
container for other files. It doesn't have any real content of its own. If
you open one of the PDF files embedded in the portfolio then the panel
should appear once more.