Bad luck at Dominos
Bill Tindall, E.Tn.
I cut tails first and mark the pin boards from these tails. It is ever so easy to get the mating parts improperly mated- left to right or front to back 
.
To lessen this opportunity I orient the drawer parts on edge on the bench. I then grab the two pieces for the corner to be marked and mate the joint for marking.
I had the two sides and back oriented on edge ready to mark. I bumped something that tipped the left side, which bumped the back, which in turn toppled the right side which spilled onto the floor, narrowly missing the soft floor mat. It hit on the top back corner half tail, which happened to have a cross grain trend. The half tail split most of its length.
Following an animated discussion with the woodworking Gods I worked glue into the split with floss and clamped it.
These half pins are weak in any case. I will need to ensure that the pin that goes next to this tail is not too tight.