S/MIME save decryption password in DeskApp

I installed S/MIME plugin and it works as expected. When I want to sign a mail, I click on the “Sign” icon, DeskApp asks for the decryption password and signs the mail.
Unfortunately DeskApp do not store the password, so I have to enter the decryption password for every mail. I enabled this parameter:

DEFINE('PLUGIN_SMIME_PASSPHRASE_REMEMBER_BROWSER', true);

Kopano 8.6.5.0
WebApp 3.4.17
SLES 12 with all patches.
DeskApp 1.9.7

Any ideas how to store the decryption password in DeskApp?
Walter

To answer my own question,
restarting Windows, now DeskApp remembers the decryption password.