Not in power... Unless of course, you count taking over the buildings surrounding the Rada. And occupying them, saying it is to make sure the members remain intimidated. There’s more than one way to be in power.
And Right Sector is indeed, in power.
Are you talking about the Ukrainian interim government? They were elected in 2012, so I think it's okay for them to "occupy" parliament. Or are you saying that "Right Sector" is occupying parliament? You're free to provide proof. I do know there is a photo of parliament when it was temporarily occupied... months before the Maidan, by Svoboda. Don't post those pictures because it will just annoy me. Please show me evidence of Right Sector holding on to government buildings.