When I type, the text appears correctly, until I type an operator (+,-,/, or space), the text disappears. It seems to go to the same color as the background, because if I delete two characters using the back-arrow key, it re-appears without the two characters I deleted.
For example,
- "3.14159" appears correctly
- "3.14159*" disappears
- Two back-arrow keystrokes and "3.1415" appears.
This is the Windows 7 and IE 11.09600.17126.