@SELECT gives unexpected results

I use the @SELECT function for menus. The window length parameter has no specified result.

set opts=%@SELECT[%prol\optiuni.lst,1,12,20,38,OPTIUNI] - I should get a window length of 19 lines.

But the last line is not displayed. Increasing the length by one i.e. (1,12,21,38) give a good result.
I was using a one column file :
word 1
word 2
...
19-th word.
When changing with a multi-columns file (more columns like in a csv file separated by semicolon) again the last line is not seen...

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