Wrapping text in ColumnsGroupViewDefinition does not affect the size of the cells.
Unfortunately there is no workaround for this issue. Make sure you cast your vote for it in order to increase its priority.
This is unbelievable!!, it is more than a year now.
Any workarounds? pleaaaaaase.
Personally, I think this is a defect and *should not* require "votes" to get fixed.