Hi @Menna Alah Ahmed
You mean you want to hide the rows, and you don't need to toggle, do you? Then you can uncheck "Display can be toggled by this report item" under Visibility.
I did a simple test to add an expression in details group visibility that doesn't show a line change when the Units value is empty.
Preview:
If the answer is helpful, please click Accept Answer
and Up-Vote
for the same. If you have any questions, please feel free to let me know.
Best regards,
Aniya