Two table visuals - second table visual shows blank if no selection made in first table visual

In my report, there are two table visuals.

1. Primary_table = Show the incident's key details (such as Incident number and total processing time)
1. Secondary_table = based on row selection on primary_table, the secondary table is used to show the selected incident's breakdown details of primary table (such as incident number, priority, name of support teams (who picked up this incidents earlier), processing time of each support team)

When user clicks on a row in primary table, the secondary table will show the breakdown details of primary table.

Primary_table
Number          Total Processing time
INC001               2 hours
INC002               3 hours

If I click on first row with Incident number = INC001, the secondary_table to show the breakdown as follows.

Secondary_table
Number      Priority        SUPPORT TEAM             PROCESSING TIME
INC001       Low            TEAM_1                                1.5 hours
INC001       Low            TEAM_2                                0.5 hours

My question:
I want the secondary table to always become blank if no user selection. I will add a card to alert the user to make selection in primary table. How to make the secondary_table shows blank in case user does not select any row in primary_table?

Unfortunately, The three functions always return "true" or value "1" even though I did not make any selection on primary_table.
Such as clicking on the empty space on the primary_table, the below three functions still returns "true" or value 1.

ISFILTERED
HASONEVALUE
SELECTEDVALUE

Please help