Include zero or nonzero values in a table by parameter

[12AMilek]

Hi,

I want to use parameter 'Dont show 0' to show only values <>0 in table. I've checked that two below formulas work, but when I use parameter it doesn't work 😞  

Notice: When parameter 'Dont show 0' is unclick table should show all records.

if( Text='Dont show 0',
           Sum( {<Customers={"=sum(Debt-Credit)>0 or sum(Debt-Credit)<0"}>} Debt-Credit),

            sum(Debt-Credit)

)

In attached .qvf file. 

Thanks for helping in advance.

[12AMilek]

Hello, any ideas how to do it?