The weight is not showing in the Drawing Partlist and in the ProSteel properties for Steel Object.
The reason for this is because no Material was selected when the element was inserted.
Please follow the below steps to resolve this.
1. Hold right click on the element and select the PS Properties > Partlist Data > Data and here select your required material and then click on the OK button.
2. Under the Values Tab check if the weight is shown. (if not toggle the Vol. weight option) once the weight is shown leaving the Volume weight option disabled.
3. To update the Partlist, double click on the Partlist then the Partlist Dialog box will show up. Go to Content Tab and then click on the Recalculate the display of the Partlist button.
In this way, we can fix this problem by assigning the material to the steel element then updating the drawing partlist.