It just happened, as far as i know.
The NCrunch Test Tool Windows is not detached, just visible. State ist Docked pinned, bottom left (all other NCrunch Tools Windows are not visible, Docked pinned Bottom right)
Today, i did not do much coding. No problems so far.
It could be that it happens more if i have multiple solutions open e.g. multiple Rider Windows (which i had yesterday)