Gadget for Google Calendar and Gmail and Google Chrome app
As Google Tasks does not support some of your unique features, it would be good to have a Tasks gadget in Google Calendar instead of Google Tasks right panel.
The same thing would be useful in Gmail and even as Google Chrome app.
Google changed API, unfortunately, now it’s impossible. Here you can see the project page https://github.com/Appiens/daybyday_gadget
AdminAppiens (Developer, Appiens) commented
Google is about to turn off some functions that we use in Day by Day gadget. Most probably the gadget will stop working, unfortunately. We expect that to happen in April :(