Select Trim Whitespace in the Extra menu to remove whitespace from the start and the end of each line. If you selected part of the file, only the selected lines are trimmed. If not, all lines in the file are trimmed.
If you’ve made a rectangular selection, EditPad Pro only deletes whitespace inside the rectangular block. Whitespace in the leftmost selected column and adjacent columns to the right is deleted. Whitespace in the rightmost selected column and adjacent columns to the left is also deleted. If a line is short and doesn’t extend to the rightmost selected column, any whitespace at the end of the line covered by the selection is deleted.
Extra|Trim Leading Whitespace
Extra|Trim Trailing Whitespace
Extra|Auto Trim Trailing Whitespace