This bug has been added to the tracker:
https://winscp.net/tracker/1457

Thanks for your tests.
I have send you another version for testing. Please respond to the email.

Yes, I confirmed. Here are the tests I tried on 2 different computers with the same results. The debug version seems to resolve the issue.

5.9.1 official installation:
- Drag and drop file from remote to desktop: "Transfer in background (add to transfer queue)" is checked.

5.9.1 official portable:
- Drag and drop file from remote to desktop: "Transfer in background (add to transfer queue)" is checked.

Debug version:
- Drag and drop file from remote to desktop: "Transfer in background (add to transfer queue)" is unchecked.

No, the debug version should not resolve anything. I didn't fix anything. The debug version is to track down the problem.
Can you try the official version again, if it still has the problem?

Martin - thanks, I confirm that the debug version you sent me resolves the issue. Thanks for fixing it.

Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

Can you please list out which preference in the screenshot you are referring to? I have both of these as unchecked: "Transfer on background by default" and "Transfer each file individually on background by default". Here is how I can reproduce:

1) In preferences, under Environments, check "Drag & drop operations".
2) Drag a file from the remote server onto local desktop.
3) Uncheck "Transfer in background (add to transfer queue)", and download file.
4) Drag a file again from the remote server onto local desktop. Note that "Transfer in background (add to transfer queue)" is checked again. Why does it stay checked each time?
5) Then downgrade to 5.7.7 and repeat. "Transfer in background (add to transfer queue)" is unchecked as expected.

Again, I do not think this has changed between 5.7.7 and 5.9.
If you have the checkbox checked by default, you must had enabled it in preferences.
See the second link in my previous post.

I think I found the issue. When I do drag and drop to download, the box for "Transfer in background (add to transfer queue)" is always checked. Even if I uncheck it, the next time it is checked again. How can I force it to be unchecked always? I had it unchecked in 5.7.7, but it is always checked each time in 5.9.1. Thanks for your help.

None of this changed. The foreground transfers are still the default as well as overwrite confirmations.

Anyway you can change both in preferences:
https://winscp.net/eng/docs/ui_pref_environment
https://winscp.net/eng/docs/ui_pref_background

Though the second issue is probably, that the overwrite confirmations are off by default for background transfers.

I recently upgraded from 5.7.7 to 5.9 and am running into 2 behavior changes. I am using the Explorer interface.

1) Downloading files via the Queue is now enabled for all my sessions rather than the old method where files would download directly with a window on top showing download progress.

2) If I download a file from a remote server to my local, I'm not being prompted to overwrite existing files. Existing files are overwritten automatically with no prompt.

Is there a way to restore these 2 functions back to what they were in 5.7.7?

Thanks for your help.

Ryan