Bugs in Mint & in T'bird (and perhaps VirtualBox)?

[markfilipak]

I suspect that I've found bugs in Mint & in T'bird (and perhaps VirtualBox). I need help isolating & confirming them.

I'm running Mint 18 64-bit Cinnamon in a VirtualBox (5.1.8 r111374 (Qt5.5.1)) VM.

There is a shared directory,
in Win7: 'c:\Users\mint\' (which is the Win7 physical store), and
in Mint: '/media/sf_mint/' (which is the Mint virtual store).
Details: In Mint, '/media/sf_mint/' appears to be an NFS share; it's actually a virtual-NFS share created within VirtualBox by means of 'vboxfs' (a Windows virtual file system driver installed and provisioned by VirtualBox).

My physical profile in Win7 is here: 'c:\Users\mint\thunderbird\0ysydkep.default', and,
in Mint, it appears here: '/media/sf_mint/thunderbird/0ysydkep.default'.

Profile 'outside' the VM = email-URLs fail.
If I use the profile outside of the Mint VM (utilizing the shared directory described above), and I make my T'bird profile absolute, pointing to the shared directory in 'profile.ini', thus:

IsRelative=0
Path=/media/sf_mint/thunderbird/0ysydkep.default

then clicking on an email-URL doesn't work, i.e., the browser does not respond: it doesn't launch, or, if already running, it doesn't open another window with the URL displayed.

Profile 'inside' the VM = normal operation restored.
However, if I 'normalize' the situation -- if I copy my profile into the VM to it's 'usual' location: '~/.thunderbird/0ysydkep.default', and I alter 'profile.ini', thus:

IsRelative=1
Path=0ysydkep.default

-- then clicking on an email-URL works as normal.

I had previously tried every solution here:
"Hyperlinks in Messages Not Working" (https://support.mozilla.org/en-US/kb/Hy ... ot-Working),
including here:
"Standard diagnostic - Thunderbird" (http://kb.mozillazine.org/Standard_diag ... hunderbird).

I suspect that message passing from T'bird to my browser (Pale Moon or Firefox), is breaking. Unfortunately, I don't know anything about Linux message passing.

• T'bird bug.
  Another thing I noticed: As I switched my default browser (via 'System Settings' > 'Preferred Applications' > 'Web') back-and-forth between Pale Moon & Firefox, T'bird did not keep up (as shown by 'Edit' > 'Preferences' > 'Attachments' > 'Incoming') even if I quit T'bird & relaunched it between changes.
  
  Curiously, in 'Edit' > 'Preferences' > 'Attachments' > 'Incoming',
  the 'https' entry did follow the changes of default browser, whereas,
  the 'http' entry did not follow the changes of default browser.
  ...I just quit & relaunched T'bird and this:

  Content Type: https - Action: Use Pale Moon (default)
  Content Type: http - Action: Use Firefox Web Browser (default)

  is what I see.
  
  T'bird bug -- Update. ...One day (and several boots) later, it appears that T'bird has now figured out that Pale Moon is the default browser for both http & https. I don't think T'bird is totally to blame because on the most recent reboot and relaunch of Pale Moon, it requested to be made the default browser -- it already was the default browser according to Mint. I'll call it a bug/quirk in Mint.

I hope folks here can make suggestions regarding how to fix the problem and how to pin the blame: Mint or T'bird or both or VirtualBox or all, so I can submit bug report(s) to the appropriate place(s). Of primary importance is replicating the bug(s) -- Is anyone here game for this?

Thanks!