# Only one onscreen window in Win version of PT?

**URL:** <https://psychtoolbox.discourse.group/t/only-one-onscreen-window-in-win-version-of-pt/800>\
**Category:** Uncategorized\
**Created:** [February 17, 2004, 10:09pm UTC](https://psychtoolbox.discourse.group/t/only-one-onscreen-window-in-win-version-of-pt/800 "2004-02-17T22:09:45Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![mogwaisc](https://avatars.discourse-cdn.com/v4/letter/m/838e76/32.png) [@mogwaisc](https://psychtoolbox.discourse.group/u/mogwaisc)\
**Post date:** [February 17, 2004, 10:09pm UTC](https://psychtoolbox.discourse.group/t/only-one-onscreen-window-in-win-version-of-pt/800/1 "2004-02-17T22:09:45Z")

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Hi,  
  
I'm just learning the SCREEN command, and so far have written a small  
program that simply displays a black screen, and then uses ASK to  
present a message "Click the mouse to continue" in the font and size  
of my choice. This works fine.  
  
However, if I try to add another SCREEN command to open a rectangle of  
a different color, I get an error saying that only one onscreen window  
is allowed in the Win version of PT.  
  
Here's my question; I'm trying to design a visual search experiment,  
where the subject will have to pick a target letter among a set of  
distracter letters displayed simultaneously on the screen.   
Theoretically, this will require me to display as many rectangles as I  
have stimulus elements that must be searched. If I can only open one  
window at a time, how in the world am I going to be able to display  
multiple objects in one window?  
  
Should I try and open them all in offscreen windows, composite them  
into a single window using the COPYWINDOW command, and then copy that  
resulting window into the onscreen window?