Tinymce: bold/italic/underline button active status are carried over to other tinymce instances

[zzs1020]

What is the current behavior? Describe the bug
If you have more than 1 TinyMCE instance, and they are inline mode. Try mark content inside first TinyMCE box as bold/italic/underline, then click on another TinyMCE box will also see bold/italic/underline buttons shows active status.
1st one:

2nd:

Please provide the steps to reproduce and if possible a minimal demo of the problem via http://fiddle.tinymce.com/FUgaab
try mark first tinymce content as bold, and then click second tinymce then check toolbar. This may also happen on all other toggle buttons and custom toggle buttons.

Also, if you have predefined \

What is the expected behavior?
shouldn't carry over status.
Which versions of TinyMCE, and which browser / OS are affected by this issue? Did this work in previous versions of TinyMCE?
tested on 5.10. and cluld version 5.0.14 both fails.

[lincolndennis]

I can confirm behavior in latest Chrome on Mac using this fiddle: http://fiddle.tinymce.com/FUgaab

Can also reproduce in 4.x.

In my testing, this behavior only occurs if you click directly from bolded content in one Inline Editor into non-bolded content in the other. It does not seem to occur if you click "out" of the first editor before clicking "into" the second.

Also, it appears to happen reliably if that is the _first_ interaction after load, but is only repeatable intermittently after that.

[lnewson]

At a glance, this looks to be caused by an issue in the formatter when using inline mode, as calling editor.formatter.match('bold') from the second editor returns true when the selection is in the bold content of the first editor.