I get the message 'Submit pending changes'

The list is attempting to submit your changes to the server before continuing with your request to refresh, navigate away from the list, or edit a calculated column. You can do one of the following:

• Wait until all changes are submitted to the server. This will allow you to resolve conflicts and errors, and resend your changes to the server, if necessary.
• Discard your changes by clicking Cancel. If you click Cancel, you will be asked to confirm whether you want to stop sending changes to the server. If you click Yes, you will lose the changes that have not yet been saved by the server. You will also not be able to resolve conflicts or errors arising from the changes that have already been submitted to the server.