I click on one remote folder. Not critical which, just needs to ensure no file is highlighted/selected.
The window is sized so that about 12-15 lines of the remote directory are seen.
Then the following problem can be reproduced:
I click (in the upper half of the right side) on a folder other than the current one
The folder is one with a dozen or so folders and a couple dozen files inside it.
I press the 'refresh' icon (two green arrows on the button)
I click on a different folder (in the top half of the right side)
I scroll down the bottom half of the right side (the file list)
I double click on a file
[problem begins here]
WinSCP scrolls the panel to the top of the file list
WinSCP tries to do a double-click on whatever file happens to be at that point where my mouse cursor was sitting
So something has happened in 5.6.3 and 5.6.4 which didn't happen in prior versions.
I have to single-click the file and THEN double-click it to get the file to open/transfer.