769992 - Scrolling a drop-down list or hovering list items or sidebar context menu is brutally slow to completely unresponsive

Status: RESOLVED WORKSFORME

(Core :: Layout, defect)

Description

[IU]

Scrolling a drop-down list or hovering list items or sidebar context menu is brutally slow to completely unresponsive.  Affects only lists and context menus tied to content.  Chrome-based menus and context menus are fine.

1. Visit http://tripplanning.translink.ca/hiwire?.a=iScheduleLookup
2. On the left-hand side, you will see a "Select Bus Route" drop-down list
3. Attempt to scroll and make selections.  Notice that it is either brutally slow or does not respond at all
4. Notice also that as you move your mouse pointer over the list items, highlighting is either brutally slow to follow, or much more the case, does not follow at all.
5. Same issue as Step 4 with the drop-down lists at http://tripplanning.translink.ca/hiwire
6. Step 4 issue also happens if you open the bookmarks sidebar and right-click an item to bring up the context menu.  Highlighting mostly fails to follow the mouse pointer on the context menu
7. Disable hardware acceleration and try again.  Notice how much worse it is.

Comment 1

[Dennis Jakobsen]

I don't see any slowness at all, it just doesn't update until mousedown or mouseup

Clicking the scroll area updates immediately. Dragging the scrollbar just does not draw until mousebutton is released.

Comment 2

[Gian-Carlo Pascutto [:gcp]]

>Chrome-based menus and context menus are fine.

Nope, they're broken as well. Visible with Livemarks in the bookmarks menu.

Comment 3

[kolubinowicki]

Attachment: Highlights of elements in menu button don't update as expected

These bug could be related with:
Bug 770069 - Dropdown mouse over highlight not working 
Bug 770021 - Context Menuitem highlight in about:addons is broken

Comment 4

[Josef Vitu]

Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/16.0 Firefox/16.0 ID:20120704030538

Works again for me in the latest Nightly (built from http://hg.mozilla.org/mozilla-central/rev/87db9617a885).

Comment 5

[Virtual_ManPL [:Virtual] 🇵🇱 - (please needinfo? me - so I will see your comment/reply/question/etc.)]

Because dlbi was backed out

Comment 6

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Smooth as silk for me (linux x86-64, basic layers).  Please reopen if it's slow for you, and list the platform and gfx configuration (accelerated or not) that you're testing with.