[Safari] Can't focus widget's editable

[kkrzton]

Steps to reproduce ¶

Note: this issue appears only on built version of CKEditor.

1. Open ​​http://tests.ckeditor.dev:1030/tests/plugins/widget/manual/block.
2. Focus the Classic editor by clicking on header like Len^na.
3. Focus caption inside first image widget like Image of Lena Söderberg us^ed in many image processing experiments..

Expected result ¶

The editable caption is focusable.

Actual result ¶

Caret jumps to the beginning of the content.

Other details (browser, OS, CKEditor version, installed plugins) ¶

Tested on Safari 10.0.1 (11602.2.14.0.7) and 10.0.1 (12602.2.14.0.7).

Happens only in classic editor, inline editor works fine.

[Marek Lewandowski]

I was able to reproduce it on built version only. Dev version works fine.

[Marek Lewandowski]

I can reproduce it with 4.6.0 so it's not a regression in this release.