If you will implement this improvement (Arrow and Home/End keys can move vertical line)
for the zero-width selection mode…
…then i have an another suggestion to make the creating
of that vertical selection line more easy (for handicapped users)
– make an normal line selection
– press an hotkey like Ctrl+Shift+L (or use an menu command) to switch to zero-width selection mode
That way there is an zero-width selection created at pos. 0 on all before selected lines.
Now we can use the arrow or end -key to move the vertical line.
.