If you have the properties set to be inherited, then when you create an idw of a part (or iam), the iproperty title field of the idw will be populated with whatever is in the part (or iam.)
If there is no value in the title field, then nothing will be written to the idw title property.
If you change the title in the ipt, the idw title will NOT automatically update, you will have to change it.
In the "Help" go to the index tab, type in "properties". Look down the list and choose "in drawings".