[plt-dev] Debugging generates internal error

Using version 4.2.0.2-svn17may2009 [3m] under linux generated an error
I cannot reproduce now:

sequence-contract-violation: negative: method set-max-width cannot be
called, except in states (unlocked write-lock), args 689

 === context ===
/home/pmatos/Applications/plt/plt-r14851/lib/plt/collects/scheme/private/more-scheme.ss:155:2:
call-with-break-parameterization
/home/pmatos/Applications/plt/plt-r14851/lib/plt/collects/scheme/private/more-scheme.ss:271:2:
call-with-exception-handler
/home/pmatos/Applications/plt/plt-r14851/lib/plt/collects/scheme/private/more-scheme.ss:155:2:
call-with-break-parameterization
/home/pmatos/Applications/plt/plt-r14851/lib/plt/collects/scheme/private/more-scheme.ss:271:2:
call-with-exception-handler
/home/pmatos/Applications/plt/plt-r14851/lib/plt/collects/drscheme/private/unit.ss:2826:8:
restore-visible-tab-regions method in ...heme/private/unit.ss:1382:6
/home/pmatos/Applications/plt/plt-r14851/lib/plt/collects/drscheme/private/unit.ss:2713:8:
change-to-tab method in ...heme/private/unit.ss:1382:6
/home/pmatos/Applications/plt/plt-r14851/lib/plt/collects/framework/private/handler.ss:94:5
/home/pmatos/Applications/plt/plt-r14851/lib/plt/collects/scheme/private/contract-arrow.ss:1364:3

If I am able to reproduce it further, I will let you know.

Cheers,

-- 
Paulo Jorge Matos - pocmatos at gmail.com
Webpage: http://www.personal.soton.ac.uk/pocm