# FIXED: offscreen color bug **URL:** \ **Category:** Uncategorized\ **Created:** [April 4, 2002, 7:00am UTC](https://psychtoolbox.discourse.group/t/fixed-offscreen-color-bug/813 "2002-04-04T07:00:21Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![denispelli](https://avatars.discourse-cdn.com/v4/letter/d/cdc98d/32.png) [@denispelli](https://psychtoolbox.discourse.group/u/denispelli)\ **Post date:** [April 4, 2002, 7:00am UTC](https://psychtoolbox.discourse.group/t/fixed-offscreen-color-bug/813/1 "2002-04-04T07:00:21Z")
hi all in october 2000, Erin Harley reported a bug. Drawing to offscreen windows referenced to screen 1 was often wrongly colored. That bug is now fixed. The new version of SCREEN.mex is enclosed. This fixed version will be included in the forthcoming Psychtoolbox version 2.5. [http://groups.yahoo.com/group/psychtoolbox/message/266](http://groups.yahoo.com/group/psychtoolbox/message/266) [http://groups.yahoo.com/group/psychtoolbox/message/881](http://groups.yahoo.com/group/psychtoolbox/message/881) i'm also including a test program, DrawTest.m, that tests for this problem, revealing the bug in version 2.44 and giving a clean bill of health to version 2.5. best denis p.s. The problem stemmed from the fact that Apple's QuickDraw operations use the color table of the current DEVICE (not the current port). This raised no issues if you were using any on-screen window, or an off-screen window associated with screen 0, which is usually the current device, but became an issue when you used an offscreen window associated with another screen. We've now enhanced a humble C routine called SetWindow to also make the offscreen window's device the current device. That fixed the bug. NOTE TO ALL: [denis.pelli@...](mailto:denis.pelli@...) is my preferred email address. Please use that address. My "verizon.net" address will go away soon, partly because Verizon forces me to use that as my "From:" address. My current email program won't allow me to designate a separate "Reply-to:" address.