1314159 - Edges of characters are clipped in Bookmarks Toolbar, after hovering, with lightweight theme that uses text-shadow

Status: NEW

(Core :: Layout, defect, P3)

Description

[Daniel Holbert [:dholbert]]

STR:
 1. Enable the Bookmarks Toolbar (right-click the toolbar somewhere, e.g. on the home button, and check "Bookmarks Toolbar")

 2. Create a bookmark on the bookmarks toolbar that ends in "y" -- e.g.:
  (a) Visit data:text/html,<title>yyy</title>
  (b) Bookmark that page, by dragging its favicon to the bookmarks toolbar.

 3. Apply a lightweight theme that adds text-shadow to your toolbars -- e.g. one of these ones:
https://addons.mozilla.org/en-US/firefox/addon/furfox-tail-twister/
https://addons.mozilla.org/en-US/firefox/addon/sdmdff/

 4. Look closely at the bottom right corner of your "yyy" bookmark.
 5. Hover and un-hover that bookmark, and look closely again.

EXPECTED RESULTS: The bookmark on my bookmark toolbar should look the same after step 4 vs. after step 5.

ACTUAL RESULTS:
* In step 4, the bottom and right edges of the "y" are nicely visible.
* In step 5 (after I un-hover), the bottom and right edges have been clipped.  (Mostly the shadow has been clipped.)

This is likely a regression from bug 1194480 (but really it's a bug in our overflow-areas computation code, and bug 1194480 just exposed it).

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: screenshot 1 (good/expected rendering on bookmark toolbar)

Here's a screenshot from Step 4 of STR (with the "good" rendering).

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: screenshot 2 (bad rendering on bookmark toolbar)

Here's a screenshot from after Step 5 of STR (with the text-shadow visibly/abruptly clipped).

Comment 3

[Daniel Holbert [:dholbert]]

I'm betting this is related to (and perhaps easier to debug than) bug 1302571.

Comment 4

[Daniel Holbert [:dholbert]]

(I'm using Linux Nightly 52.0a1 (2016-10-28) (64-bit), BTW.)

Comment 5

[Daniel Holbert [:dholbert]]

You can see this in tab-titles, too, if you use slightly different STR:
 STR 2:
  1. Open a tab that has a "y" at the end, like data:text/html,<title>yyy</title>
  2. Install a theme that uses text-shadow on tab-titles, like
      https://addons.mozilla.org/en-US/firefox/addon/furfox-tail-twister/
  3. Visit the page for a theme that *does not* use text-shadow, like this one:
      https://addons.mozilla.org/en-US/firefox/addon/on-a-hill/
  4. Hover & un-hover the theme preview image.

If I look carefully at your tab with the "y", I can see that the shadow is nice before step 4, but it gets clipped at the bottom & right of the "y" after step 4.  (It gets fixed if I hover the tab, though.)

Comment 6

[Daniel Holbert [:dholbert]]

Attachment: screenshot 3 (bad clipping on tab title)

Comment 7

[Julien Cristau [:jcristau]]

Mass wontfix for bugs affecting firefox 52.