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 5.7.6
Error message:
Canvas does not allow drawing
Stack trace:
(001BF82F)
(004313A7) @Tbx@TTBXToolbar@WMEraseBkgnd$qqrr29Winapi@Messages@TWMEraseBkgnd
(002177D1)
(0021C315)
(0021B95C)
(003402A8)
(000152F7) USER32.dll
(00016311) USER32.dll.GetDC
(00015DE3) USER32.dll
(00015E41) USER32.dll
(0000F107) ntdll.dll.KiUserCallbackDispatcher
(0001F74C) USER32.dll
(001E0598)
(000A9791)
(00002462)
(007E2811)
(00038880) ntdll.dll
(00038850) ntdll.dll
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.