Minimize button doesn't work while delete is in progress

If you are deleting a large number of files via FTP, the buttons in the top-right corner, including the minimize button, become unresponsive. I know you can use the minimize button in the 'Deleting' dialog, but it's kind of counterintuitive, and it took me a while to realize that it was even there.

Is there a reason that the minimize button is disabled during deleting?

Using Windows 8.1 x64

WinSCP progress window is modal, so you cannot use other windows of WinSCP while an operation is ongoing. While I understand this is not user friendly, and we would like to change this in long term, it's quite a huge change, so it takes time.