Dialog tab is disabled if has content elements of html type only (same as ticket 13193)

[chad.rehm]

Steps to reproduce

1. download and use mytest.zip​ by j.swiderski on ticket 13193. ​https://dev.ckeditor.com/ticket/13193
2. add an id to the outermost html element div '<div id="someid" class="tab_container">' on tab 1.
3. open dialog
4. select tab 2 then try to select tab 1.

Expected result

selecting tab 1 will bring you back to tab 1 one

Actual result

once tab 2 is selected tab 1 can't be reselected.

Work Around

html: '<div class="tab_container"><div id="myDiv"></div></div>',

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