1257579 - Hit-testing doesn't work properly in some cases on desktop builds with resolution

Status: RESOLVED DUPLICATE of bug 1556556

(Core :: Panning and Zooming, defect, P3)

Description

[Kartikaya Gupta (email:[e-mail])]

(Follow-up issue from bug 1242690)

STR:
- Nightly desktop build (I used Linux, probably happens everywhere though)
- Set dom.meta-viewport.enabled to true
- Set apz.allow_zooming to true
- Restart browser
- Open about:newtab and resize the window to something smaller than width 980.
- Mouse over the tiles on the new-tab page and observe when they get the "hover" effect

Expected:
- They should get the hover effect when any part of them is hovered

Actual:
- They only get the hover effect on a subsection of their area. If you resize the window down too much they might not get any hover effect at all.

From experimenting with this it seems like there's a clip being applied somewhere in the chain that's not taking the resolution into account. Note also that about:newtab lives in the parent process, so that might be relevant. Pages in the child process generally don't have any problem with hit-testing under this configuration.

I strongly suspect this is related to issues discussed previously in bug 1243514 and bug 1228602. I tried a few things including hunks of the unlanded WIP patches referenced in those bugs but didn't make much headway.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

Marking 48 as unaffected because none of the desktop builds allow zooming by default, this isn't something we need to worry about until we enable zooming.

Comment 2

[Botond Ballo [:botond]]

I cannot reproduce this with bug 1556556 in the tree. The hover effect is activated correctly over the entire area of the new tab tiles, including when zoomed in.