Weird, for me it starts up in whatever the last tab I had open was. If it was the store, it opens to the store, if I was updating something it opens to the updates tab (even if there aren't any updates to install).
Ditto.
Hey LightStar; in the past I have seen Impulse do this and some other funky little things, this was when I was running Beta versions, I now only run the stable release versions and never have any little funky things happen.