Dropdown list based on a datasource table in another sheet in excel

Hi
I am not sure if the title indicates my issue correctly. I have a example.xlsb (attached here) developed by some one else. There are 2 sheets Log and Datasource in the workbook. Datasource sheet stores the drop down lists used in the Log sheet. To replicate my issue please do as follows:
1. In Log sheet, select 'Surfacings' in cell A2. This will add a whole bunch of cells with values. - which is intuitive. Not sure how it does that behind the scenes.
2. Cell F1 = Surfacing Type and cell F2 gets a dropdown list from DataSource!$D$2:$D$5. When i click on the Data validation for Log!F2 - the Source shows: =INDIRECT(SUBSTITUTE(F1," ","")) and selecting it automatically choses the Table (SurfaceType): DataSource!$D$2:$D$5.

All the above are working correctly.
3. I tried replicating the same by adding a new column: Weight in the DataSource sheet in Cells E2:E5 and named the Table: MatlColl.
4. However I do not know how to get the dropdown in the Log sheet for Cell G2 to show the list from my new table (i.e. DataSource sheet in Cells E2:E5). . This is my issue.

Appreciate any help.

Regards
docgee