Can you reproduce the problem in the latest version of WinSCP?
Something apparently worth reporting concerning v. 5.7.6, on windows 7, SFTP, commander interface. When closing a session containing several tabs I get the following notice: Cannot focus a disabled or invisible window.
Stack trace:
(001DB8F9) Vcl::Forms::TCustomForm::SetFocus
(00749F76) TEditorForm::FormCloseQuery
(001DB48D) Vcl::Forms::TCustomForm::CloseQuery
(00015A18) TCustomScpExplorerForm::FormCloseQuery
(001DB48D) Vcl::Forms::TCustomForm::CloseQuery
(0021C315) Vcl::Controls::TWinControl::WndProc
(001D70B8) Vcl::Forms::TCustomForm::WndProc
(0078D54D) Vclcommon::C2516_0
(0021B95C) Vcl::Controls::TWinControl::MainWndProc
(003402A8) System::Classes::_18201
(000152F7) USER32.dll
(00015D35) USER32.dll
(00015DE3) USER32.dll
(00015E41) USER32.dll
(0000F137) ntdll.dll.KiUserCallbackDispatcher
(00015A87) USER32.dll
(00016742) UXTHEME.DLL
(0001908D) UXTHEME.DLL
(0000FB0A)UXTHEME.DLL
(0000FB91)UXTHEME.DLL
(00016294) USER32.dll
(000152F7) USER32.dll
(00015D35) USER32.dll
(0001FD3A) USER32.dll
(0001FD60) USER32.dll.CallWindowProcW
(0021C426) Vcl::Controls::TWinControl::DefaultHandler
(001DA49D) Vcl::Forms::TCustomForm::WMSysCommand
(0021C315) Vcl::Controls::TWinControl::WndProc
(001D70B8) Vcl::Forms::TCustomForm::WndProc
(0078D54D) Vclcommon::C2516_0
(0021B95C) Vcl::Controls::TWinControl::MainWndProc
(003402A8) System::Classes::_18201
(000152F7) USER32.dll
(00016311) USER32.dll.GetDC
(00015DE3) USER32.dll
(00015E41) USER32.dll
(0000F137) ntdll.dll.KiUserCallbackDispatcher
(00015A87) USER32.dll
(00016742) UXTHEME.DLL
(00025E80) UXTHEME.DLL
(0000FB0A)UXTHEME.DLL
(0000FB91)UXTHEME.DLL
(00016294) USER32.dll
(000152F7) USER32.dll
(00015D35) USER32.dll
(0001FD3A) USER32.dll
(0001FD60) USER32.dll.CallWindowProcW
(0021C426) Vcl::Controls::TWinControl::DefaultHandler
(0021C315) Vcl::Controls::TWinControl::WndProc
(001D70B8) Vcl::Forms::TCustomForm::WndProc
(0078D54D) Vclcommon::C2516_0
(0021B95C) Vcl::Controls::TWinControl::MainWndProc
(003402A8) System::Classes::_18201
(000152F7) USER32.dll
(00015D35) USER32.dll
(000167BF) USER32.dll
(00016885) USER32.dll.DispatchMessageW