After 2 minutes do you still not see layout editor in the "Open With" menu?If so could you share any interesting errors from your browser console?

Is it missing immediately after entering the IDE or even 2 mintues after it loads?

You can't do it from this dialog. You need to do File -> Open Workspace... Then choose projects.After that you'll see all those folders in file explorer and you'll be able to delete them.

If you don't use multi root workspaces feature then workspace is actually a folder.You can delete them from the terminal or opn projects as workspace and then delete them from the tree UI.I'm not familiar with other way to do it.