How to disable files from staging when using SourceTree on Mac?

I've looked for the answer, and found that the .jsf file may hold the solution. however couldn't find such file on mac.

The issue is when I click the check box of an un-staged file, the file automatically transforms to "staged files" window. I'd like to disable this option, and similarly to PC, I'd like to manually stage my files when choosing "stage file" from the "..." menu.

How can I make this change?

Thank you