There is no necessary to save your file. Imagine, you need to delete lines with e.g. 5 different searchses. When you will do copy nonmatching line, you will get the result in new window. Then you can continue with new window content and finally copy result from the last file into first one and save.
The otther possibility is made search with regular expressions and put there all search variation into one expression -- <https://forum.pspad.com/read.php?2,70766,70807> PSPad freeware editor https://www.pspad.com
