I use Opera and have a setup with two monitors. If I want to open a new URL opera -newwindow URL. The outcome differs, if I execute this command in a program on the same screen where Opera is, or on the other.

On the same screen everything is fine. I get the message opera: Activated running instance and the new window with the URL is opened.

On the other screen, I get a dialog with the following message: It appears another opera instance is using the same configuration directory because its lock file is active: /home/(my name)/.opera/lock and the URL is not shown.

That's not only from console, also if I click a link in E-Mail or so. How can I fix this?

Window-manager is awesome, if it does make a difference.