bug#47360: 27.1; using 'bar cursor, mouseclick is rounded to the wrong char position

[Eli Zaretskii]

> Date: Sat, 27 Mar 2021 17:53:41 +0000
> From: Julian Rohrhuber <rohrhuber@protonmail.com>
> Cc: Lars Ingebrigtsen <larsi@gnus.org>, Eli Zaretskii <eliz@gnu.org>, 
> 47360@debbugs.gnu.org
> 
> There is one more case where one can feel the difference: when selecting with 
> the mouse and dragging to the right, the selection jumps to each character a 
> little "too late", that is, after you have already crossed the position you 
> want the selection to end at. You have to point to a character *after* the 
> one you want to include. The current selection always is up to one character 
> behind the cursor barline.  This results in a "sticky" feeling.

Yes, selection in Emacs works on per-character granularity, because it
uses the faces infrastructure.  We'd need to do something very
different to make that use pixel granularity.  Patches are welcome.