1329658 - Selecting content using SHIFT+UP/DOWN is broken for content that contains form controls

Status: NEW

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

Description

[Mats Palmgren (inactive)]

STEPS TO REPRODUCE
1. select a few "a" in the first word
2. type three CTRL+DOWN (or whatever the select-to-next-line command is on Mac)
3. copy-paste the selection somewhere
4. click somewhere on the background of the page to "reset" the selection

ACTUAL RESULTS
Some c's at the end are selected, these are copied in step 3.
However, the a's you selected are still painted as selected although
they were never copied in 3 (they are in fact not part of the selection
anymore).  In step 4 the a's still appear selected.

There are many variations of the STR that are broken:
select some c's then type CTRL+UP a few times
select some b's then type CTRL+DOWN a few times
select some d's then type CTRL+UP a few times

The general bug seems to be that when selecting over a form control (or anything
with native anonymous content), the current selection is lost when the caret
pass over it.

The underlying root cause is similar to bug 1328030.

Comment 1

[Mats Palmgren (inactive)]

Attachment: testcase

Comment 2

[Mats Palmgren (inactive)]

Doh, when I say CTRL above I mean SHIFT, of course. :-)

Comment 3

[Mats Palmgren (inactive)]

In case someone wants to pick this up, the code to fix is the eSelectLine case here:
http://searchfox.org/mozilla-central/rev/b1044cf7c2000c3e75e8181e893236a940c8b6d2/layout/generic/nsFrame.cpp#7930
and/or the GetNextPrevLineFromeBlockFrame function here:
http://searchfox.org/mozilla-central/rev/b1044cf7c2000c3e75e8181e893236a940c8b6d2/layout/generic/nsFrame.cpp#7344