1327802 - <listbox> element in UI sometimes adds blank lines when quickly scrolled to the end

Status: RESOLVED WORKSFORME

(Core :: General, defect)

Description

[arni2033]

>>>   My Info:   Win7_64, Nightly 49, 32bit, ID 20160526082509
STR_1:
1. Open about:preferences#applications
2. Click on dropmarker "Always ask" near selected content type, click "Use other..." menuitem
3. {drag scrollbar thumb to the top, then quickly drag scrollbar thumb to the bottom} several times

AR:  Sometimes blank lines appear at the bottom of the <listbox>
ER:  No blank lines


STR_2:  (details and advices on how to reproduce the bug)
1. Open about:preferences#applications
2. Click on dropmarker "Always ask" near selected content type, click "Use other..." menuitem
3. Open new FF window. Open from 5 to 10 tabs with http://www.rp-online.de/ ,
   depending on how fast your PC is (obviously, if it's fast, open 10 or even 20 tabs)
4. Right-click any tab in the window opened in Step 3, click "Reload all tabs"
5. While tabs are loading, switch to tab opened in Step 1, then
  {drag scrollbar thumb to the top, then quickly drag scrollbar thumb to the bottom} several times

Comment 1

[ovidiu boca[:Ovidiu]]

I can't reproduce it on Mac OS X 10.10 with FF Nighlty 54.0a1 (2017-01-31).

Comment 2

[Firefox Bug Husbandry Bot]

Moving from Core::Untriaged to Core::General https://bugzilla.mozilla.org/show_bug.cgi?id=1407598