When the Pulsar goes nova the motion stops (nothing is frozen though) and the ability to select objects breaks (I couldn't select anything) even if I load a different simulation nothing can be selected. The only solution is to restart the software.
To reproduce:
Open>Binary Pulsars>Select any of two stars> increase the mass until it goes nova> try to select anything else
It looks like this bug was introduced in Alpha 15.2, in Alpha 15 it is not present. Sorry if this bug was reported before, I searched but failed to find anything similar.
P.S. the feedback window is bugy as well, I failed to select the first letter and copy paste the text from there to here.