fixed Dev mode

src-tauri/src/launcher.rs

@@ -887,7 +887,10 @@ impl Launcher {
       // launch: `dev_engine` would quietly hand back the installed version, and the window
       // would go on saying the run came from the checkout. Being told the folder is wrong
       // while looking at it beats wondering later why an edit changed nothing.
-      if next.dev_mode {
+      // Only a folder that was NAMED is checked. Dev mode is switched on from the hub now,
+      // and the checkout is chosen next to the Launch button afterwards, so refusing the
+      // switch for an empty folder would refuse the first half of a two-step job.
+      if next.dev_mode && !next.dev_root.is_empty() {
         let build = PathBuf::from(&next.dev_root).join("ODIAN_Engine").join("tools").join("build").join("build.bat");
         if !build.is_file() {
           return Err(format!("{} is not there: the dev folder is the one HOLDING ODIAN_Engine.", build.display()));