You are of course right, I totally misread the proposed patch, sorry! :-)
I will ask our team to merge it, but I think it would still be great to have allow_cancel raise an exception with a clear message instead, so people pressing the Cancel button understand why it does not do anything (it should perhaps be named check_cancel if it does not return a boolean)
@Dukai Gábor:
You are of course right, I totally misread the proposed patch, sorry! :-)
I will ask our team to merge it, but I think it would still be great to have allow_cancel raise an exception with a clear message instead, so people pressing the Cancel button understand why it does not do anything (it should perhaps be named check_cancel if it does not return a boolean)