Before I log an issue... in Pharo 7 using Calypso to run a test by clicking its status-dot, when trying to step <Over> a semaphore #wait the UI locks up. I presumed this was due to the #wait effectively occurring in the main UI thread, so I solved this by forking the test as follows. Is that a reasonable thing to do? ClyRunTestsFromMethodsCommand >> runTest: testSelector of: testClass [ | testResult | testResult := testClass debug: testSelector. self notifyUserAboutResults: testResult with: 'Method: ' , testClass asString , '>>#' , testSelector asString ] forkNamed: 'TESTING ' , testClass asString , '>>#' , testSelector asString With that change, you can step over a #wait as if it wasn't there, which IIRC is in line with the old behaviour. Now a bit of a dream, but even better would be that just the debugger stepping over the #wait was suspended (rather than the whole UI) with an indication like a red border. When the #wait was signaled, the red border would disappear and the debugger might jump to the top. cheers -ben