This feature is currently in Beta.  Switch to Beta.

Update your Wavebox to the Beta Channel, and click on any email address to reveal a shiny new email picker, showing a list of ALL your webmail addresses. Just click on the one you need to launch a compose window ready for your message.

Here's how to get it working in just two simple steps.

Pick your Default Browser and Email Client.

r/waveboxapp - Wavebox + Emails = 💖

Start by setting Wavebox as your default browser and default mail handler. You can do this easily in Settings > Default Browser & Handlers.  Click on the 'Make Default' button for each.

Click and Compose.

r/waveboxapp - Wavebox + Emails = 💖

Find an email address in any app on your OS, or in Wavebox, to see the email picker modal in action.  Choose the account you need to open a new compose window for that account.

There are also options to copy the address to clipboard if needed, and to open in a new app window (not signed-in).