What's App Blocks Vivaldi for me, so I don't know how to add it as a WebPanel, but try right-clicking on the Panel Icon and using the Desktop Version.
[image: 1555314147074-whats-up-resized.png]
Specs: AMD A10-6800K, 8 Gb on Win 10 64-bit 1809 build 17763.437 • Snapshot 2.5.1511.4 (64-bit)