File status and read-only files
The editor tabs, or editor selection menu when the tabs are hidden, indicate the status of the file by appending * when the file has been edited or (r/o) when the file is read-only. This information is mirrored for the current file in the status area at the bottom left of each editor window. Edited status is also shown in the Window menu by appending * to the file names found there.
Files that are read-only on disk are initially opened within a read-only editor. Use the file's context menu (right-click) to toggle between read-only and writable state. This alters both the editability of the editor and the writability of the disk file so may fail if you do not have the necessary access permissions to make this change.