Toolbar doesn't accurately reflect active font/size in Safari

[routman]

Quill 1.0 has no issues in Safari upon initially loading the editor, but once you start repeatedly manipulating it via the API, it stops accurately reflecting the active font and size when you move your cursor around. There are a number of ways that I can reproduce this, but the codepen below is one simple example. This only happens in Safari in both Mac and iOS. Chrome works fine.

One strange thing is that once you reproduce the problem, then open developer tools in Safari, the problem goes away.

Steps for Reproduction

1. Visit http://codepen.io/routman/pen/GqaVNy
2. Move your cursor to "the grey"
3. Then move your cursor to "Gandalf".

Expected behavior: When you move your cursor to "Gandalf", the font dropdown should say "Monospace" and the size should say "Large".

Actual behavior: The dropdown remains on "Sans Serif" and the size remains on "Normal", but changes to a blue color.

Platforms: Safari 9.1.2 in OS X 10.11.6 and Safari in iOS 9.3.4

Version: 1.0.0-rc.2

[DanielHaroldLane]

Just for clarification, when you say move your cursor over "the grey" do you mean to hover the cursor, or to click somewhere in the text "the grey" to move the caret? If you mean the former then it's functioning normally, if you mean the latter than there's a problem.

[routman]

When I say move the cursor, I mean to click anywhere in the text. If you click "the grey", then click "Gandalf", the problem occurs. Same thing happens when you click "the grey", then left-arrow the cursor over to "Gandalf".

[jhchen]

It seems like dataset might actually be unreliable in Safari. I added a line to log dataset.value and getAttribute('data-value') which to my knowledge should always return the same thing.

Switching to only using getAttribute does indeed fix the problem which is what I'll do for Quill but if someone can reduce the bug with a simpler setup, it would be informative to know if Quill is doing something wrong with the DOM API or if a bug needs to be filed for Safari.