Invalid access to memory - TCustomScpExplorerForm::Idle

<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 6.1.1

Error message:
Invalid access to memory.

Stack trace:
(0001B8A5) TCustomScpExplorerForm::Idle
(00097FAF) ntdll.dll
(00076221) ntdll.dll.KiUserExceptionDispatcher
(00053267) TNonVisualDataModule::DoIdle
(00053224) TNonVisualDataModule::SessionIdleTimerTimer
(00214D98) System::Classes::_18201
(00046CD0) USER32.dll
(00026095) USER32.dll
(000249C3) USER32.dll
(000244FB) USER32.dll.DispatchMessageW

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.

@Andy: Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

<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 6.1.2

Error message:
Invalid access to memory.

Stack trace:
(0001B8A5) TCustomScpExplorerForm::Idle
(0009812F) ntdll.dll
(00077D31) ntdll.dll.KiUserExceptionDispatcher
(00053267) TNonVisualDataModule::DoIdle
(00053224) TNonVisualDataModule::SessionIdleTimerTimer
(0021564C) System::Classes::_18201
(00031E51) USER32.dll
(00022C21) USER32.dll
(000214E0) USER32.dll
(0002102B) USER32.dll.DispatchMessageW

The problem happens rarely. I cannot reproduce it.