Without clearAllMarkers, you can see that the alt buffer decorations persist on the screen until the normal buffer is rendered. The search addon disposes the decorations/markers then on the onWriteParsed() event. Adding clearAllMarkers disposes them before clearing the all buffer.

It might be even better to add clearAllMarkers to the clear function of the buffer (?)

EDIT: The search-addon decorations are very hard to see with the background changes.

@silamon since markers are changing to work also in the alt buffer we'll need to cover all marker use cases, this means making them invalid when alt -> normal happens. To validate which solution is best you could also run this while the alt buffer is up:

const m = term.registerMarker();

Switch the the normal buffer and make sure m is now disposed.

The search-addon decorations are very hard to see with the background changes.

Do you mean the demo theme changes? The demo's options.theme isn't tied to the search theme currently and it's probably overkill for the demo. You can always switch the theme now though:

It might be even better to add clearAllMarkers to the clear function of the buffer (?)

Adding to clear would call it in the normal buffer as well and I think there might be a problem with that. Just doing it for the alt buffer is the safer approach.