Sorry to post it here again. I have not had any feedbacks from the Help forum.

I found pspad can automatically adjust the width. It uses 1-2 columns for <100 lines and 3 columns for <1000 lines. 

The line number margin in Notepad++ has 5 to 6 columns and it is fixed. It takes quite space on my notebook screen. Is there any way to adjust it?

Thanks,

Phil