Editor: Multi-selection with Alt+Shift and Home or End

Multi-selection with Alt+Shift and Home or End should select symbols, not create new cursors.

Steps to reproduce:

• open attached "1.txt" file
• create multi cursors in center of lines, as in "initial.jpg"
• press Alt+Shift and End

Expected: right half of lines should be selected, as in "good.jpg"

Actual: new cursors are created at the end of lines, as in "bad.jpg"