<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.15.1

Error message:
メモリのアクセス違反

スタック トレース:
(0021A14C) Vcl::Graphics::TBrush::SetColor
(00087D7F) ntdll.dll
(00073221) ntdll.dll.KiUserExceptionDispatcher
(00273CC5) Vcl::Controls::TControl::WndProc
(00273900) Vcl::Controls::TControl::Perform
(00278CB2) Vcl::Controls::TWinControl::PaintControls
(00278AB1) Vcl::Controls::TWinControl::PaintHandler
(002791C0) Vcl::Controls::TWinControl::WMPaint
(0027E599) Vcl::Controls::TCustomControl::WMPaint
(00278809) Vcl::Controls::TWinControl::WndProc
(00277E50) Vcl::Controls::TWinControl::MainWndProc
(003A346C) System::Classes::_18201
(00043449) USER32.dll
(00023F87) USER32.dll
(00023B25) USER32.dll
(0002D16D) USER32.dll
(000731DB) ntdll.dll.KiUserCallbackDispatcher
(00022EBB) USER32.dll.DispatchMessageW

The problem happens rarely. I cannot reproduce it.