1772396 - Page Breaks Do Not Propagate to Parent When They Don't Place Between Siblings

Status: NEW

(Core :: Layout, defect)

Description

[David Shin[:dshin]]

As per the standard: "Since breaks are only allowed between siblings, not between a box and its container [...] break values applied to children at the start/end of a parent are propagated to the parent, where they can take effect."

Comment 1

[David Shin[:dshin]]

Attachment: testcase 1: Break Propagation Test Case

Expected: The attached test case should paginate without any div stretching across pages.
Actual: Outer div containing "b" stretches across page 1-3.

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: testcase 2 (same as 1 but with thicker borders)

I noticed that the 1px borders in testcase 1 don't show up for me in print-preview (due to them being scaled-down for the small print-preview visualization, which effectively rounds them to zero). This makes it slightly-harder to visualize. I imagine they can be seen with Retina/HiDPI resolutions, but they're invisible on my non-HiDPI monitor.

Anyway: here's a testcase with 3px borders instead, to make them more-likely to show up in print preview, for easier analysis/visualization.)

Comment 3

[Daniel Holbert [:dholbert]]

(In reply to Daniel Holbert [:dholbert] from comment #2)

I noticed that the 1px borders in testcase 1 don't show up for me in print-preview (due to them being scaled-down

(I filed bug 1775345 on this, BTW.)

Comment 4

[Ting-Yu Lin [:TYLin] (PDT, UTC-7)]

Attachment: Testcase 3 (reduced from bug 1663079 comment 5)

This testcase is reduced from the testcase in bug 1663079 comment 5.

The Line 2 (gray box) should be solely in page 2, but Firefox currently render it immediately after "Line 1".