In a multihead setup with 2 screens, If I open gnome-terminal from the
primary screen like gnome-terminal --display :0.1 or gnome-terminal
--screen 1 the terminal is opened in the secondary screen. 

When I open gnome-calculator from the terminal in the secondary screen
which is started by the above method calculator opens in the primary
screen. When I did a echo $DISPLAY in the above terminal it gives :0.0
though it is opened in the secondary screen (:0.1). 

Simillar things happens with gnome-calculator.
1. gnome-calculator --display :0.1 (from a terminal in primary screen)
2. gnome-calculator comes in the secondary screen
3. Invoke help from gnome-calculator, the help is displayed in primary
screen instead of the secondary screen

One more thing is
1. open gnome-terminal in the secondary screen, either from the
Applications  menu or by right clicking on the secondary screen desktop
2. Invoke help of the terminal, help is displayed in the secondary screen
3. Save session and then logout and login
4. terminal and the help contents come in the secondary screen as expected
5. If the help of the terminal is invoked again it is opened in the primary
screen
6. Same applies to all applications.

Thanks.