To resolve the issue of not being able to copy material onto the ChatBox app screen, follow these steps:

1. Ensure Proper Selection: When attempting to copy text, make sure you are correctly selecting the desired portion. Sometimes, selections might inadvertently extend to the entire chat, leading to confusion. Try highlighting the text directly without dragging.

2. Use Shift and Command: If you find that copying and pasting doesn't work as expected, hold down the Shift and Command keys while copying. Then use Command + V to paste the text into the ChatBox. This method has helped users overcome pasting issues - learn more.

3. Restart the App: Close and reopen the ChatBox app. This can often resolve temporary glitches that interfere with copying and pasting functionality.

4. System Clipboard Check: Ensure that your system clipboard is functioning properly. Sometimes, issues with the clipboard can impede the copy-paste process. Testing copy-paste functionality in other applications (like TextEdit or Safari) can help confirm that it's working as it should.

5. Update the App: Make sure you are using the latest version of the ChatBox app. Developers frequently release updates that address bugs and improve functionality. If there's an update available, install it and see if the issue persists.

6. Check Permissions: Verify that the ChatBox app has the necessary permissions to access the clipboard. This might be found in your MacOS System Preferences under Security & Privacy settings.

7. Reboot Your Computer: If none of the above steps work, try rebooting your Mac. A fresh start can sometimes clear out underlying issues that cause copy-pasting to behave inconsistently - learn more.

8. Community Support: If after trying all these steps the problem continues, consider reaching out to community forums like Reddit or the official OpenAI community for specific advice based on your version or troubleshooting related to the app - learn more.

By systematically following these steps, you should be able to restore the ability to copy and paste material into the ChatBox app successfully.