Drawing tool hangs after clicking on a nuclide whose graph is empty

[ferdymercury]

I can usually click on some elements and view the decay scheme. But sometimes, when I enter on some line, a blank screen appears, and all the subsequent attempts on different nuclei, even those that worked well before, fail.

I get the warning:

Pd-93 LEVEL  Spins=(45/2+) comment=A
      Gamma: Pd-93 GAMMA  Intensity(phot)=8±2
QGraphicsItemGroup::addToGroup: cannot add null item
QGraphicsItemGroup::addToGroup: cannot add null item
QGraphicsItemGroup::addToGroup: cannot add null item