Didn't report because I guess it is by design, but just to confirm: is it intended that in 1.0 M2 every menu (Navigator|Sites|Repositories|Console|Get Plugins) opens as a new browser tab?
There is now a preference in the user settings to control this. I don't know if it was a deliberate decision to change the default... personally that drives me crazy and I immediately switch back so I can have user control over when tabs are created.