When Enigmail in Thunderbird needs to open a passphrase protected key the
pinentry window does not show up. Thunderbird hangs. If you close thunderbird
the pinentry then shows up.
This appears unrelated to the "hidden in the background" error which happens if
you run GnuPG on the command-line. Here the window really doesn't appear anywhere.
The default pinentry.exe appears to be the qt4 pinentry. I'm not sure if I have
QT4 installed however. IF you simply cp pinentry-w32.exe to pinentry.exe it
works. Perhaps the more compatible w32 pinentry should be used by default?
gpg (GnuPG) 2.0.14 (Gpg4win 2.0.2)
Enigmail 1.1.2
Thunderbird 3.1.1