1582487 - Shift+upward_arrow key behaves weirdly when selecting and deselecting text

Status: NEW

(Core :: DOM: Selection, defect, P3)

Description

[kumar]

Attachment: firefox.gif

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:69.0) Gecko/20100101 Firefox/69.0

Steps to reproduce:

• Go to the any source file on Github
  for example: https://github.com/mozilla/pdf.js/blob/master/pdfjs.config
• Select some text (at least 3 lines either by using touch-pad/mouse or double click the text and then press shift+downward_arrow)
• Now, press shift+upward_arrow key to deselect some text at least twice times.

Actual results:

Texts are not getting deselected after pressing shift+upward_arrow key combination more than once. Only first time text gets deselected after that no text gets deselected no matter how many time I press shift+upward_arrow key and if number shift+upward_arrow key pressed is more than difference between initially selected and current line then it will start selecting text in upward direction (which is expected) but, without deselecting below text (which is unexpected).
I try to verify that whether FF only shows selected text incorrectly by copy & pasting the selected text but, found that FF copies exact same text as it's showing in blue colored line (selected text).

I've recorded a screen-cast which is attached below in which I press shift+upward_arrow key and copy & paste selected data to a snippet. And, in right hand side there is a box which shows keys I pressed.

I can reproduce this bug on Gitlab and many more websites. And even sometimes shift+downward_arrow key also behaves weirdly.

Expected results:

Text should get deselected as I press shift+upward_arrow key if current line is below initial selected line otherwise, start selecting text from just above the initially selected line.

Comment 1

[Pablo]

Reproduced the issue on the following OS:

Windows 10 64bit
MacOs 10.14
Ubuntu 18.04 64bit

With all these Firefox versions:

Firefox Nightly release 71.0a1 : affected
Firefox Beta release 70.0b8 : affected
Firefox Release 69.0.1 : affected

Comment 2

[Pablo]

-->selection
may be a duplicate of bug https://bugzilla.mozilla.org/show_bug.cgi?id=127884