When setting WrapMode to false it is possible to scroll 10 characters to the left.

While this is already strange it gets confusing when combined with a vertical column header.

See the following examples:

Opened a file with a single long line. Set WrapMode to false:

Scrolled 10 characters to the left:

Set a vertical column header of 15 characters. See that the content after the column header is calculated wrong. It should start at m (the 16th character), but instead starts at e (the 5th character).