Backspace and Ctrl+W issues with html5 forms and flash.
I'm using Apache Guacamole and some flash text input fields in other web apps.
Pressing Ctrl+w will close the window, Backspace will load the last accessed page of that tab. This does not happen in Firefox or IE/Edge. The web application tries to catch those inputs, and in fact, the key will be send to the web application. I can see this with guacamole: After reopen the tab, the window inside my VNC session was closed.
Please see that web applications can capture AND OVERRIDE those (and other) keyboard shortcuts. Not just capture, but also override them. This makes vivaldi unusable at the moment.
BTW: Same issue in chrome(ium).
(Search the forums for "backspace flash" without the quotes).