I tried removing the beginning and end chunks of SourceFrame.js (can't say what they were exactly, since I could not undo the deletes), but I did roughly this: SourceFrame.js: A B C (where A, B, C are rather big chunks consisting of full lines) 1. Put caret at the beginning of the first line of B 2. Ctrl-Shift-Home, Delete 3. Put caret at the beginning of the first line of C 4. Ctrl-Shift-End, Delete 5. Ctrl-Z, Ctrl-Z. At this point, the entire contents of the file were just two characters: "/*" (unquoted) - only the first line of the file. I also had a bunch of JS errors in the console (perhaps, some were added after some more experiments): Uncaught Out of bounds:1 (TextEditorModel.js:224) Uncaught TypeError: Cannot call method 'substring' of undefined (TextEditorModel.js:422) Uncaught TypeError: Cannot call method 'insertBefore' of null (DefaultTextEditor.js:2638) (2) Uncaught TypeError: Cannot read property 'offsetTop' of undefined (DefaultTextEditor.js:924) Uncaught TypeError: Cannot call method 'insertBefore' of null (DefaultTextEditor.js:2638) (2) Uncaught Error: NotFoundError: DOM Exception 8 (View.js:462) Uncaught Out of bounds:1 (TextEditorModel.js:224)
Closing as invalid, as this bug pertains to the old inspector UI and/or its tests. Please file a new bug (https://www.webkit.org/new-inspector-bug) if the bug/feature/issue is still relevant to WebKit trunk.