You probably know the inevitable Get(OpenRecordState) calc function, that helps us a lot, for instance on a script triggered by OnRecordLoad or OnRecordCommit.
But certain new developer may ignore the fact that this calc function also works like a charm if used as an unstored calc, defined on a related table.
Thus, you can, in the same context previously stated, test if portal row were created or modified during the current activation of the main record.
By the way, you also can define a List aggregate field to know instantly if, yes or no, there were a row created or modified, and directly go to them in a loop.
In a minor way, this trick may also could be useful on a conditional formatting.