Tested the same on win8.1 chrome version 51.0.2704.84 and canary - Tool tip not displayed on the grey color box

same is observed in Firefox as well.

IE displays the tool tip on both boxes

This is a non regression issue existing since M30 builds to latest canary
Confirming the issue for further inputs on this.

I can reproduce this on Linux in 51.0.2704.84 (Official Build) (64-bit) (and Firefox 47.0--interesting coincidence.)

Moving this nonessential bug to the next milestone.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

FYI, I'm investigating this bug.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/58b15addedd3cb872fedf1d7a9c88fce8c35e0de

commit 58b15addedd3cb872fedf1d7a9c88fce8c35e0de
Author: mrunal.kapade <mrunal.kapade@intel.com>
Date: Fri Mar 03 21:38:38 2017

Fix the way <title> is read under <use> shadow tree

Earlier there was no way <title> element could be read under <use> shadow
tree. By implementing title() override in SVGUseElement we return first <title> child under <use> if there is any.
Otherwise we return the first <title> child from the shadow tree instance under <use>.

BUG= 619073 

Review-Url: https://codereview.chromium.org/2706583002
Cr-Commit-Position: refs/heads/master@{#454683}

[add] https://crrev.com/58b15addedd3cb872fedf1d7a9c88fce8c35e0de/third_party/WebKit/LayoutTests/svg/dom/tooltip-title-with-use.html
[modify] https://crrev.com/58b15addedd3cb872fedf1d7a9c88fce8c35e0de/third_party/WebKit/Source/core/svg/SVGUseElement.cpp
[modify] https://crrev.com/58b15addedd3cb872fedf1d7a9c88fce8c35e0de/third_party/WebKit/Source/core/svg/SVGUseElement.h

We went with only considering direct <title> children of the referenced element, to align somewhat with the name computation algorithm from the SVG AAM [1]. As such, "<title>derpy</title>" would need to be a direct child of <symbol> to be picked up as a tooltip.

[1] https://www.w3.org/TR/svg-aam-1.0/#mapping_additional_nd

(assigning this to myself as a proxy for mrunal.kapade)