Suppose it is caused by the file with very long(column) text in one line or some lines.
For example:
1,000,000 lines of “0123456789\n” , 12MB,
View “Wrap by Window” => Vertical bar is smooth; Horizontal bar is N/A.
View “No Wrap” => Vertical bar is smooth; Horizontal bar is N/A.
Try to remove all “\n”, it will become 1 line of “012345678901234567890123…..”, 10MB,
View “Wrap by Window” => Vertical bar is not smooth; Horizontal bar is N/A.
View “No Wrap” => Vertical bar is N/A; Horizontal bar is not smooth.