Dev Mode: Revert to saved is refused there (it throws unsaved design edits away)

crates/engine/src/devinspect.rs

@@ -220,11 +220,13 @@ pub struct DevItem {
 
 /// Whether Dev Mode runs command `id` from the menus and shortcuts: commands that don't edit the
 /// document, and Dev Mode's own edits (annotations, statuses, dev resources, code connections,
-/// comments). Choosing a tool other than moving around and commenting is refused too.
+/// comments). Choosing a tool other than moving around and commenting is refused too, and so is
+/// Revert to saved, which isn't an undo step but throws the design's unsaved edits away.
 pub fn dev_mode_allows(id: &str) -> bool {
     const OWN: [&str; 5] = ["annotation.", "dev.", "devResource.", "codeConnect.", "comment."];
     match id.strip_prefix("tool.") {
         Some(t) => matches!(t, "move" | "hand" | "comment"),
+        None if id == "file.revert" => false,
         None => OWN.iter().any(|p| id.starts_with(p)) || crate::cmd::find_command(id).is_none_or(|c| !c.history),
     }
 }

crates/engine/src/devmode_behaviour_tests.rs

@@ -123,6 +123,7 @@ fn dev_mode_runs_its_own_edits_and_refuses_design_edits_from_menus_and_shortcuts
         "tool.text",
         "tool.place",
         "file.import",
+        "file.revert",
     ] {
         assert!(!dev_mode_allows(id), "{id} edits the design");
     }