"Using Symbols, Emoticons and Special Characters" won't display

When clicking "Insert" and then "Symbols", a new window will pop up without anything inside - its blank (see attachment). This occurs while using Internet Explorer 11 @ Windows 7 (32-bit).
With Firefox (Version 31.8.0) the symbols are visible after hitting the "Insert">"Symbols"-Button but the line on the bottom ist "cut in half" (see second attachment).