I checked Pinta 1.7 source code and compared it with Pinta 1.8. It appears there are differences in file Pinta/Actions/File/CloseDocumentAction.cs
See attachment.
I checked Pinta 1.7 source code and compared it with Pinta 1.8. It appears there are differences in file Pinta/Actions/ File/CloseDocum entAction. cs
See attachment.