Add a "Problems" panel to the editor
Add a "Problems" panel under the editor, similar in display as the references panel in the viewer.
The design of the panel should be similar to the one in VS Code, and could be used for a bunch of different issues, like spell checking, formatting checks, file issues like from #1344, etc.
If this panel can be hidden, it would most certainly be nice. Why would I like to hide this panel? When a problem shows up in the mentioned panel, I must fix it now, or it will occupy my OCD mind for eternity.
I'm taking this out of planned features until there is something to actually show in this panel. The idea was to show spell check errors, but for now that's not high priority.