What is backgroundnumber for?

[Pulcik]

Hi guys,

just wandering, what is "backgroundnumber" parameter in addbackground() function for? Can not find the use for that parametr. Is it some "legacy" parametr?
It even seems, that normal person can not write this parametr in "screen editor". It is only accessible in the .ssf code. Or, am I missing something?

[cncdrive]

Background number parameter means the picture image number used for the backgroung on the tab control.
The image numbers list with the image paths/names are in the screen editor on the images tab page of the screen editor window.