Question about IE

Hello everybody.

I'm using ckeditor V4.0.1

When I use IE (11) if I try and highlight some text to (eg) change the font, font size, style etc as soon as I click on the drop down list for font or font size, etc the text is de-selected. I can use bold, italic etc ok, it only seems to be the drop down selections that give this problem.

BUT everything works fine on Chrome, Firefox & Chromium

I note that on this forum it works on IE  - is there some set up I am missing?