Item will be deleted if user tries to change name and delete old name with backspace

If user wants to rename some content from timeline and double click old name and then press backspace there comes "Rename Object Error - Object name cannot be an empty string." and after that user needs to click ok and content is deleted from timeline.

One way to reproduce:

1. Add Basic Object eg. Cube from Basic objects
2. Double click Cube from timeline to rename it. 
3. Name will be selected
4. Press Backspace
5. Error message occurs
6. Click Ok

      -> Object is gone from timeline.

There should be somekind of message like: Object name cannot be an empty string. Add name etc.