Feature/minor u ifixes

* Reorganizing first launch
* Minor ui edits

Solving issues 
#145 #155 
Good advance to issue
#116 
@vincentadam87 , what does it mean if there's an `IllegalArgumentException`? Does it mean the receiver is already unregistered? Or can it mean something else? If it means there's a problem we should throw a `new RuntimeException()`, and there should be some logging and a comment regardless :p.