• VSCode Version: Code 1.19.3 (7c4205b, 2018-01-25T10:36:34.867Z)
• OS Version: Windows_NT x64 10.0.16299
• Extensions: Extensions are disabled

Steps to Reproduce:

1. Create a new text file with 4000 empty lines
2. Put the cursor on the first line
3. Scroll to bottom
4. Alt + Click on the last line to add 3999 more cursors
5. Press Delete key or Backspace key
6. You should notice the deletion takes a lot of time

But if the cursors are not consecutive, deletion will be much faster.

To illustrate the problem:

If the cursors are positioned like this (| represents a cursor position):

|
|
|
|
|
|

The deletion will be very slow.

If the cursors are positioned like this (just by pressing Enter in the last case):

|

|

|

|

|

The deletion will be a lot faster.