How to get Claws Mail to download an over sized message

[sunrise@mailbug.com]

Hi,

I am using Claws Mail 3.9.3 with POP3 and have 'size_limit=3000' in
~/.claws-mail/accountrc to limit downloading of messages larger than 3MB. Normally,
when displaying a partially downloaded message, Claws Mail would display a button
labeled as 'Mark for Download' that can be selected to request it to retrieve the rest of
the message on the next connect. However, for some reason, the 'Mark for Download' button
is not always displayed, and the only indication that the message was only partially
retrieved is that the attached file does not open properly, as it is not complete.

So my question is: Is there any way to force Claws Mail to retrieve a specific message
that has not been completely downloaded? Or how does the Claws Mail GUI normally mark a
message for download when the aforementioned button is clicked?

Thanks for any ideas.

--
Jason