Window becomes unresponsive after a while when synchronizing

Hi! Using WinSCP 5.5 on Windows 8 x64.

This is quiet difficult to reproduce, but I use the "Keep remote directory up to date" practically all the time. The problem is the WinSCP window becomes slow to response after a while of using it.

This is most annoying when using VirtuaWin (Open Source) virtual desktops, since it cannot hide or unhide the window when it's unresponsive. It keeps saying me it's waiting for the WinSCP window to become responsive again.

It does work after I wait several seconds between change of desktops, or as I have gotten used to stop the synchronization.

I suspect it's a threading problem, the WinSCP main window that takes the minimize/restore/show/hide commands gets somehow bogged when running synchronization for a long time.

Btw, VirtuaWin works very well with other programs such as Adobe Photoshop, Eclipse, etc. which are way more resource hungry programs.

This is not a new problem, it's been in WinSCP for ages.

Thanks for your report.

Is it unresponsive while synchronizing (transferring files) only or even when idle (waiting for change)?
How long does it take approximately for the problem to start happening? Does it depend rather on time the "Keep remote directory up to date" function is running or on number of synchronizations done?

It is usually staying idle (waiting for change) I make changes to files only on few desktop and not very often.

Sometimes couple of minutes, sometimes longer, I can try to evaluate it better.

It usually occurs when I switch back to the desktop where WinSCP is synchronizing, then it takes couple of seconds or more for WinSCP to "wake up", but it only slows down to this after it's been running for considerable periods of time.

I think the VirtuaWin uses by default the ShowWindow() SW_SHOW, SW_HIDE, I've also tried with other methods with no help.