TYPO3 Core

That's weird.
Clicking the icon should move the focus to the datefield which will then in return trigger the datepicker.
I do not get the error on Firefox, but can reproduce on IE9 and 10.

I can not confirm this issue on Firefox on Mac. But The Datefield of the Stop-Date (Expiration Date) is not useable for me.

Icons are shown in Firefox and IE as well.

In IE (even 11): Although the click on the icon does focus the input field, it doesn't show the date picker. But focusing the input field manually works just fine. I have tried to find any issue but I have no clue.

Can't reproduce on FF either, but IE11 has this issue.

I tried to debug a bit: My conclusion is that IE somehow does not trigger the focus event when clicking the label.
I wanted to modify the bootstrap datetimepicker to add a console.log() but it always uses the min.js version, which I did not fiddle around with.

So it would be necessary to confirm this thesis first.

Clicking the label (the icon) in IE11 shows the datepicker for a very, very short time if the input field is empty. In this case there is also an onChange event (attached with the onChange="" attribute) which is triggered in IE11 (inserted a tracepoint in the IE debugger on TBE_EDITOR.fieldChanged).
Still a mystery what goes wrong with showing the datepicker itself...

Attaching the t3js-datepicker class to DIV wrapper makes the date picker appear when clicking the label, but it doesn't work on the INPUT field anymore.
Next thing was to add an extra onClick="document.getElementById('formengine-input-HASH').click();" attribute for testing. In this case a click is forced on the INPUT field, but the same behaviour appears in IE11: if the field is empty the datepicker appears for some tenth of a second, if the field is filled it is not visible.
The example in
http://eternicode.github.io/bootstrap-datepicker/?markup=component&format=&weekStart=&startDate=&endDate=&startView=0&minViewMode=0&todayBtn=false&clearBtn=false&language=en&orientation=auto&multidate=&multidateSeparator=&keyboardNavigation=on&forceParse=on#sandbox
(also an icon after the form and a clear button inside if a date is set)
works flawlessly in IE11.

My FireFox problem is solved now after resetting to defaults.

In the latest master I still have some problems with IE11 when I click on the calender icon the pop-up won't show.

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at http://review.typo3.org/38885