Why does not PtDivider allow to change the size/dimensions of its childs at runtime using PtSetResource()?

I wasn't able to manage resize PtText/PtButton childs in the PtDivider container using PtSetResource(). Neither of 
Pt_ARG_MIN_WIDTH,  Pt_ARG_MAX_WIDTH, Pt_ARG_WIDTH, Pt_ARG_DIM has any effect. According to documentation there is the 
Pt_CALLBACKS_ACTIVE flag in Pt_ARG_FLAGS to allow calling the drag callback (if set) when any child changes its size. 
This flag led me to idea that it's possible to change the childs size at runtime. But it seems I was wrong. Or is it 
really possible?