Not sure if this is really a bug or just an improvement idea, but I happened to notice that in the File Types edit menu (for example when editing the context menu for All Files and Folders), there is a confirmation box that appears when you click the 'Delete' button with an item selected, but no confirmation box if you delete via Right Click > Delete.
I would imagine it's more likely that one will accidentally click Delete from the right click menu (like when going to copy and paste an item) than hitting the button, so maybe the right click Delete should also have the confirmation box.
Though accidental deletions can still be brought back by hitting cancel though at least.
As a separate possible idea for the future, it might be nice to have a "restore default items" button in each File Type's menu that brings back any deleted default menu items. I'm imagining one that wouldn't over-write the existing items added by the user, just add back any original items that aren't there anymore.