Interacting with controls without loosing focus of active window?

Hi,

is there some way to interact with controls without loosing focus of the active window? I need to fill in InputBoxes of a program I start hidden but when it starts I loose focus of my active window and when I switch back the data that should be written to the controls of the hidden program are written into the active window instead?

I dont want that "solution" btw:


Maybe there is some way to actually interact with these controls without even giving the program the focus?

Please enlighten me