Bug Report: Overwrite vs Resume

I use WinSCP 4.2.7 to transfer files back and forth between a Windows XP Virtual Machine and a Ubuntu 10.04 host. What will often happen is that I will modify a file on XP, making it larger than its previous version, before transferring it back to Ubuntu.

Every time this file is to be copied, it asks me if I want to resume the file transfer, and presents me with an option to never ask again. When I select the checkbox, the option to overwrite becomes disabled. For copying many files at once, having to click No twenty times is a bit of a pain.

Steps to Reproduce:
1. Create simple text files on remote machine
2. Copy said files to local machine using WinSCP
3. Add content to beginning of files on local machine
4. Copy files back to same directory on remote machine as original files
5. When prompted to resume file transfer, select "Never ask me again"
Expected: Able to click no, not asked this question again, local and remote files match
Observed: "No" option disabled

It is my hope that this bug will be corrected at the earliest opportunity.

What protocol are you using?

I'm having an issue with transfers that get interrupted. Sometimes when I try and download something that is incomplete, WinSCP asks to resume it. Other times, it just completely overwrites and deletes the original file. This is a problem. Some of these files are hundreds of gigabites and take days to download. I am losing a lot of time and business because WinSCP refuses to throw up a confirmation dialog to either overwrite or resume the transfer. I don't have any idea why it sometimes works and sometimes doesn't. It's a total gamble. I'm using FTP on Windows 10.

I wanted to edit my post to change folder to file and ended up quoting myself and making a big mess of things. You guys could really use an edit function on here. And for god sake, would you change your captcha method? It took me an entire two minutes to get it to accept my answers. I can't tell you how many damn traffic lights, fire hydrants, motorcycles and buses I had to click to get here.

@joyu: Please attach a full session log files showing both scenarios (using the latest version of WinSCP).