I'm using KP 2.19 atm. I have the same error with at least 3 or 4 previous KP2 versions.
My file is locked and when I double click on the tray icon, I get asked for the password.
I enter it correctly and I get asked for my password again without an error message.
I abort the second password dialog and my file is unlocked without any errors. This
only happens with double clicks on the tray icon.
You may have set the tray icon to open on single click. Try one click.
No. It's set to open with a double click
Right click, Unlock only asks for the password once?
Try minimizing to the task bar, then a single click will be enough to request the master key.