[0.9.4] cannot add child widget because its NULL

[LoSboccacc]

Hi I got this error while right clicking on an assembly machine 2




I was trying to reproduce another logistic related crash:

I opened a requester chest, removed in fast succession all the item inside (that caused a crashbug earlier that I need to reproduce)
this time it didn't crash anything

however, when I right clicked on the assembly machine, I got that message and game quit

[LoSboccacc]

I can reproduce it 100% when building an assembly machine 2 with blue science pack recipe from blueprint

[kovarex]

Thanks for the report, it is fixed for 0.9.5 now.