Comment #3 on issue 1044 by chisvasi...@gmail.com: Can't debug block local variables in GT debugger http://code.google.com/p/moose-technology/issues/detail?id=1044
This bug also appears with the standard debugger from Pharo 3 and I guess it's a combination of two things: - ifTrue: is inlined - the debugger does not recognize variables from the workspace (https://pharo.fogbugz.com/f/cases/12432)
I'll open a bug report on the Pharo issue tracker.