Bug report: Access Violation when dropping columns from large table

The table is large ~10 million rows. When I drop a column I get an error. However, it seems to complete the operation successfully because the columns are gone after I restart HeidiSQL.

Here's the report....
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date/time : 2013-01-20, 02:42:06, 919ms
computer name : [obfuscated]
user name : [obfuscated] <admin>
registered owner : Windows User
operating system : Windows 7 x64 Service Pack 1 build 7601
system language : English
system up time : 11 hours 1 minute
program up time : 1 hour 33 minutes
processors : 2x Intel(R) Pentium(R) 4 CPU 3.06GHz
physical memory : 251/1278 MB (free/total)
free disk space : (C:) 112.25 GB
display mode : 1280x1024, 32 bit
process id : $37c
allocated memory : 52.92 MB
executable : heidisql.exe
exec. date/time : 2012-02-12 13:45
version : 7.0.0.4053
compiled with : Delphi XE
madExcept version : 3.0m beta 1
callstack crc : $4eb49e1d, $369d539d, $369d539d
exception number : 1
exception class : EAccessViolation
exception message : Access violation at address 00632A43 in module 'heidisql.exe'. Read of address F64F753C.

main thread ($f20):
00632a43 heidisql.exe VirtualTrees TBaseVirtualTree.GetNodeLevel
007e1448 heidisql.exe Main 6838 +2 TMainForm.DBtreeInitNode
0062710b heidisql.exe VirtualTrees TBaseVirtualTree.DoInitNode
0062b011 heidisql.exe VirtualTrees TBaseVirtualTree.InitNode
00630f9f heidisql.exe VirtualTrees TBaseVirtualTree.GetDisplayRect
0063386f heidisql.exe VirtualTrees TBaseVirtualTree.InvalidateNode
0063ea53 heidisql.exe VirtualTrees TCustomVirtualStringTree.InvalidateNode
006269e7 heidisql.exe VirtualTrees TBaseVirtualTree.DoFocusNode
0062ab38 heidisql.exe VirtualTrees TBaseVirtualTree.HandleMouseDown
004e9314 heidisql.exe Controls TControl.DoMouseDown
00622b50 heidisql.exe VirtualTrees TBaseVirtualTree.WMLButtonDown
0062ee63 heidisql.exe VirtualTrees TBaseVirtualTree.WndProc
004ecc20 heidisql.exe Controls TWinControl.MainWndProc
004ab4d8 heidisql.exe Classes StdWndProc
74cc7885 USER32.dll DispatchMessageW
00575b6b heidisql.exe Forms TApplication.ProcessMessage
00575bae heidisql.exe Forms TApplication.HandleMessage
00575ed9 heidisql.exe Forms TApplication.Run
007fc8fb heidisql.exe heidisql 67 +16 initialization
762733a8 kernel32.dll BaseThreadInitThunk