Cannot change Visible in OnShow or OnHide

This bug happens when trying to synchronize folders by pressing Ctrl+S buttons.

WinSCP 5.10

Error message:
Cannot change Visible in OnShow or OnHide

Stack trace:
(00215B14)
(00834B88)
(00257A85)
(00211F4C)
(008385B4)

Status: unknown_rel_addr

I know how to reproduce the problem or the problem happens frequently enough. I wish to be contacted by the WinSCP team to help resolving the problem.

Thanks for your reports.

This bug has been added to the tracker:
https://winscp.net/tracker/1539

I'm sending you an email with a development version of WinSCP to the address you have used to register on this forum.