mozilla/addon-sdk — pull request #496 by ochameau (2012-07-16 17:01:14+00:00)
Title: Bug 758283: try to fix test-tab-browser.testTabModuleActiveTab_getterAndSetter 

Second try to fix this. I hope it is the good one, but it is hard to tell without running on tbpl ...
The new failure was that these 4th tabs being opened were dispatching an activate event too.
While we only expect `tm1.activeTab = tab1;` to generate one!