Use CTRL + ALT + A to show/hide WhatsApp in your active browser tab. Use CTRL + ALT + -/+ to decrease/increase WhatsApp frame opacity.
Add-on is avaliable here: https://addons.mozilla.org/en-US/firefox/addon/work-n-wapp/
josip-volarevic/Work-n-Wapp
Simple Mozilla Add-on that lets you integrate whatsapp into your work environment
JavaScript