After Vivaldi 1.9 release with Ecosia search engine, Vivaldi team has released first snapshot of Vivaldi 1.10 for Windows, Mac and Linux platforms and the most requested feature sought by developers was in it. Vivaldi 1.10 snapshot features docked developer tools. Till now Vivaldi is launching devtools in a separate window, now docks to right side of the main window by default.
Of,course you can click on three vertical dots button (customize and control dev tools) and undock devtools to a separate window, or dock to bottom, or dock to left or dock to the right (default). Apart from this new feature, the snapshot brings better thumbnails for speed dial folders.
Firefox 52 devtools: New Responsive Design Mode