I'm so sorry for the delayed reply. I did not see the email and I forgot about this issue until now, when I bumped into it again.
To recreate this problem you could clone my repo
and open a *.vhd file placed in src/hdl
From there
* open the speedbar
* select Speedbar > Displays > VHDL Directories
From there, with the pre-installed vhdl-mode you can not expand the files (by typying the '+' symbol at the beginning of every file name), while if you install vhdl-mode from source, the file expands as it is supposed to.
I will attach a screenshot on how the expansion should look like with vhdl-mode
Thank you,
sorry again for the late reply.
Filippo