Linux Mint Maya if it matters...
For the past couple of years one (only) of my four Mint machines has been opening windows behind the current one, necessitating either clicking on the icon on the task bar or dropping the current window to the task bar.
An example is opening a New or Reply box in thunderbird, but non-mozilla apps do it as well.
I read, when this first happened, that it was a safety feature - you couldn't accidentally type a password into a newly opened window by accident. I can no longer even find that reference. :(
Does anyone know how to overcome this and return new windows to the foreground when they open? Please?