Editora 0.18.3. Archived, so links from that release keep working. Read the 0.18.5 page →
LSP: Toggle Project-Wide Problems
lsp.toggleProjectProblems Switch the Problems window between open files and the whole project.
How to run it
Open the command palette (M-x in the Emacs keymap) and search for LSP: Toggle Project-Wide Problems, then press Enter. It has no default keybinding, but you can bind one in Settings → Keymaps.