A remote window should behave like a window on this Mac. Where Wormhole falls short of that, or behaves differently on purpose, it is listed here rather than left for you to find.
Both Macs need the same keyboard layout
Not supported yet
Keys are sent as the physical key you pressed, and the Mac that shares turns them into characters with its own keyboard layout. If one Mac uses a different layout (AZERTY on one, US on the other), what arrives is the other layout's character. Switch both to the same input source for now.
Clicking a remote window brings it to the front on the other Mac
By design
A click or a keystroke can only reach the window that is in front, so the Mac that shares raises the window and activates its app when you click into it. On a Mac mini with no one at it, nobody notices. On a Mac someone is using, their window order changes.
⌘Q, ⌘H, ⌘M, ⌘Tab and ⌘` stay on this Mac
By design
Every other ⌘ shortcut goes to the remote app. These five act on this Mac: ⌘Q closes the remote window here rather than quitting the app over there, and ⌘H, ⌘M, ⌘Tab and ⌘` hide, minimise and switch as they always do. ⌘W is not one of them: it closes the real window on the other Mac.
Without Accessibility, a shared window is view-only
By design
The Mac that shares needs Accessibility turned on to pass clicks and typing to its windows. Without it you can watch, and the window tells you once that input is off and where to turn it on.
In whole-screen mode, typing goes to whatever is in front
By design
A shared display has no single window to send keys to, so keystrokes go to the app that is in front on the other Mac, exactly as if they were typed on its own keyboard.
Copying folders, and anything over 20 MB, between Macs
Not supported yet
Copy and paste between your Macs carries text, images and files, but not folders, and nothing larger than 20 MB in one copy. Copy the files inside a folder instead, or move large files another way.
A Mac mini with no display attached
Not tested yet
Not tried yet on a real headless mini. With no display attached, macOS can have nothing to draw windows on, and the picker then says so. An HDMI dummy plug, a small adapter that tells the Mac a display is connected, fixes it.
Password fields, games and some Electron apps
Not tested yet
Password fields on the other Mac (macOS protects them with secure input), games that read the keyboard and mouse directly, and some Electron apps have not been tried yet. If one of them does not take your input, write to support and say which app: it will be listed here either way.
Found something that is not listed? Email hello@wormhole.buildmac.app with the app and what you pressed.