Error while closing query tab

Hi,

I sometimes get an error while closing a query-tab. Can´t say what to do to reproduce this.

Here the callstack:
date/time : 2011-02-15, 16:30:06, 336ms
computer name : WSJH2
user name : jh <admin>
registered owner : Microsoft / Microsoft
operating system : Windows 7 x64 build 7600
system language : German
system up time : 7 hours 35 minutes
program up time : 7 hours 16 minutes
processors : 2x Intel(R) Core(TM)2 Duo CPU E8500 @ 3.16GHz
physical memory : 2538/3738 MB (free/total)
free disk space : (C:) 221,25 GB
display mode : 1600x1200, 32 bit
process id : $978
allocated memory : 71,24 MB
executable : heidisql.exe
exec. date/time : 2011-02-15 09:13
version : 6.0.0.3691
compiled with : Delphi XE
madExcept version : 3.0m beta 1
callstack crc : $00000000, $17ec5b7e, $17ec5b7e
exception number : 4
exception class : EAccessViolation
exception message : Access violation at address 00000000. Read of address 00000000.

main thread ($53c):
00000000 ???
004d61e8 heidisql.exe Controls TControl.GetClientWidth
005b9ccd heidisql.exe Buttons TSpeedButton.MouseUp
004d8ba8 heidisql.exe Controls TControl.DoMouseUp
004d8c24 heidisql.exe Controls TControl.WMLButtonUp
004d8208 heidisql.exe Controls TControl.WndProc
004dcacc heidisql.exe Controls TWinControl.WndProc
0056d3c0 heidisql.exe Forms TCustomForm.WndProc
004d7e2c heidisql.exe Controls TControl.Perform
004dc16c heidisql.exe Controls TWinControl.MainWndProc
004d7e2c heidisql.exe Controls TControl.Perform
004dc3f8 heidisql.exe Controls TWinControl.IsControlMouseMsg
004dc948 heidisql.exe Controls TWinControl.WndProc
004dc16c heidisql.exe Controls TWinControl.MainWndProc
004a56ec heidisql.exe Classes StdWndProc
75c67df5 USER32.dll DispatchMessageW
0057638f heidisql.exe Forms TApplication.ProcessMessage
005763d2 heidisql.exe Forms TApplication.HandleMessage
005766fd heidisql.exe Forms TApplication.Run
00796752 heidisql.exe heidisql 66 +15 initialization
756a3675 kernel32.dll BaseThreadInitThunk

Still got this error (sometimes).
Here´s another Dump (with other hex-values):

date/time : 2011-03-03, 11:07:47, 655ms
computer name : WSJH2
user name : jh <admin>
registered owner : Microsoft / Microsoft
operating system : Windows 7 x64 build 7600
system language : German
system up time : 2 hours 7 minutes
program up time : 11 minutes 20 seconds
processors : 2x Intel(R) Core(TM)2 Duo CPU E8500 @ 3.16GHz
physical memory : 2227/3738 MB (free/total)
free disk space : (C:) 220,65 GB
display mode : 1600x1200, 32 bit
process id : $d88
allocated memory : 63,49 MB
executable : heidisql.exe
exec. date/time : 2011-03-02 10:58
version : 6.0.0.3707
compiled with : Delphi XE
madExcept version : 3.0m beta 1
callstack crc : $00ffffff, $5cabe67b, $5cabe67b
exception number : 1
exception class : EAccessViolation
exception message : Access violation at address 00FFFFFF. Read of address 00FFFFFF.

main thread ($adc):
00ffffff ???
004d621c heidisql.exe Controls TControl.GetClientWidth
005b9d01 heidisql.exe Buttons TSpeedButton.MouseUp
004d8bdc heidisql.exe Controls TControl.DoMouseUp
004d8c58 heidisql.exe Controls TControl.WMLButtonUp
004d823c heidisql.exe Controls TControl.WndProc
004dcb00 heidisql.exe Controls TWinControl.WndProc
0056d3f4 heidisql.exe Forms TCustomForm.WndProc
004d7e60 heidisql.exe Controls TControl.Perform
004dc1a0 heidisql.exe Controls TWinControl.MainWndProc
004d7e60 heidisql.exe Controls TControl.Perform
004dc42c heidisql.exe Controls TWinControl.IsControlMouseMsg
004dc97c heidisql.exe Controls TWinControl.WndProc
004dc1a0 heidisql.exe Controls TWinControl.MainWndProc
004a5720 heidisql.exe Classes StdWndProc
753f7df5 USER32.dll DispatchMessageW
005763c3 heidisql.exe Forms TApplication.ProcessMessage
00576406 heidisql.exe Forms TApplication.HandleMessage
00576731 heidisql.exe Forms TApplication.Run
0079674a heidisql.exe heidisql 65 +15 initialization
76c93675 kernel32.dll BaseThreadInitThunk

There were 3 tabs opened:
- closed the 2nd tab -> error
- closed the 3rd tab (now the 2nd) -> error
- opened and closed a tab -> error
- opened 2 tabs
- closed 3rd one -> no error
- closed 2nd one -> error

The problem is gone after restarting Heidi

Please try out r3711. I am very unsure why that happened, and I did not came across this AV often enough to get the cause of it. However, r3711 avoids calling some functions which I suspect to be buggy.