It works just fine for me in Firefox ESR 45.0.1 and PaleMoon 26.2.1. TOR browser should also cause no issues - as it is also based on Firefox ESR.
For IE11 ctrl+v does not work in the default editor, I agree.
For the HTML editor it is still possible to copy/paste in IE11 and then to switch to the default editor.
Is there absolutely no option for you to use a different browser?
There are also portable browser versions available - if you are unable or unwilling to install them as applications. If you give the portable browsers a chance, you might even like them better than IE.