Hi.
Can you give more details on how you got into this state:
- Are you editing the default tilesheet that was created at project initialization, or another image?
- Do you have the image opened in another software?
- Did you made any changes to the project settings?
- Can you open the developer tools (View > Toggle Developer Tools) go onto the "Console" tab if not already selected, and tell me if you see any logs or errors in there?