Joining newline-separated lines by backspace deletes characters

[dcsaszar]

Expected behavior.

Only the line break between the lines is removed, effectively joining two lines into one. (FooBar)

Actual behavior.

Two more characters are removed from the end of the 1st line. (FBar)

Steps to reproduce the problem.

https://jsfiddle.net/Le2usdvx/

• initial text with an actual newline:

  Foo
  Bar
  

  (This makes most sense with white-space: pre, but works without it, too)
• Position the cursor at the start of "Bar"
• Press backspace

Editor version.

4.1.1 and earlier

OS.

MacOS 13.5.1 (22G90)

Browser.

Chrome 116.0.5845.140

Recording.

[liborbus]

Seems to be related to issue #4700