Widget nested editable triggers blur event on focus in Firefox

[mflorea]

Type of report

Bug

Provide detailed reproduction steps (if any)

1. Open https://jsfiddle.net/7t4wvg06/6/ using Firefox
2. Open the JavaScript console (Developer Tools)
3. Click over "foo" to focus the widget (inside the CKEditor's editing area)
4. Type something in the widget
5. Click below "foo" to blur the widget (i.e. outside of the widget)

Expected result

Step 3 should log

editable focus

and step 5 should log

editable blur

Actual result

Step 3 logs

editable focus
editable blur

and step 5 doesn't log anything.

Other details

• Browser: Firefox 61.0.1
• OS: Ubuntu 17.10
• CKEditor version: both 4.10.1 and 4.10.0
• Installed CKEditor plugins: copyformatting

It doesn't reproduce on Chrome or if you remove the copyformatting plugin.

My investigation shows that this is a regression caused by 3a9f058 which was committed in CKEditor 4.10.0 . The change for Firefox is that

editorFocus: false,

has become

editorFocus: true,

so the applyFormatting command requires the editor to be focused but in my case I don't call this command explicitly so I don't understand how it affects the widget.

[engineering-this]

@mflorea thank you for your report. I can confirm this bug.

[Comandeer]

The issue was fixed by #2792. The fix will be released in 4.11.3.