Created attachment 415136 [details]
File: backtrace

#2  <signal handler called>
No symbol table info available.
#3  0x0000003d97284220 in _wordcopy_fwd_aligned () from /lib64/libc.so.6
No symbol table info available.
#4  0x0000003d972828f2 in memmove () from /lib64/libc.so.6
No symbol table info available.
#5  0x00007ffd1883eabc in nsMsgDBView::RemoveRows (this=0x7ffd0d285c00, 
    viewIndex=1063, numRows=4)
    at /usr/src/debug/thunderbird-3.0.4/comm-1.9.1/mailnews/base/src/nsMsgDBView.cpp:5209
No locals.
#6  0x00007ffd1883d89d in nsMsgDBView::CollapseByIndex (
    this=<value optimized out>, index=<value optimized out>, pNumCollapsed=
    0x7fffb15c178c)
    at /usr/src/debug/thunderbird-3.0.4/comm-1.9.1/mailnews/base/src/nsMsgDBView.cpp:4784
        rv = 0
        flags = <value optimized out>
        rowDelta = -4
        numRemoved = 4
#7  0x00007ffd1884baa9 in nsMsgThreadedDBView::MoveThreadAt (this=
    0x7ffd0d285c00, threadIndex=1062)
    at /usr/src/debug/thunderbird-3.0.4/comm-1.9.1/mailnews/base/src/nsMsgThreadedDBView.cpp:810
        collapseCount = 32765
        preservedSelection = {<nsTArray<unsigned int>> = {<nsTArray_base> = {
              static sEmptyHdr = {mLength = 0, mCapacity = 0, mIsAutoArray = 
    0}, mHdr = 0x7fffb15c17a8}, <No data fields>}, mAutoBuf = 
    "\000\000\000\000\001\000\000\200\000d\251\375"}
        threadFlags = {<nsTArray_base> = {static sEmptyHdr = {mLength = 0, 
              mCapacity = 0, mIsAutoArray = 0}, mHdr = 
    0x7ffcfb8f7920}, <No data fields>}
        currentIndex = 0
        saveFlags = 1207959696
        threadIsExpanded = 1
        threadLevels = {<nsTArray_base> = {static sEmptyHdr = {mLength = 0, 
              mCapacity = 0, mIsAutoArray = 0}, mHdr = 
    0x7ffcf6114210}, <No data fields>}
        changesDisabled = 0
        hasSelection = 1
        threadKeys = {<nsTArray_base> = {static sEmptyHdr = {mLength = 0, 
              mCapacity = 0, mIsAutoArray = 0}, mHdr = 
    0x7ffcfb8f7900}, <No data fields>}
        newIndex = <value optimized out>
        lowIndex = 52428784
        threadHdr = {<nsCOMPtr_base> = {mRawPtr = 
    0x7ffcf43cf6a0}, <No data fields>}
        childCount = 4
        preservedKey = <value optimized out>
        selectionCount = 32765
        highIndex = <value optimized out>
#8  0x00007ffd1884bd40 in nsMsgThreadedDBView::OnNewHeader (this=
    0x7ffd0d285c00, newHdr=0x7ffcf4539220, aParentKey=<value optimized out>, 
    ensureListed=<value optimized out>)
    at /usr/src/debug/thunderbird-3.0.4/comm-1.9.1/mailnews/base/src/nsMsgThreadedDBView.cpp:690
        flags = <value optimized out>
        threadCount = 3
        threadFlags = 0
        threadRootIsDisplayed = 0
        moveThread = 1
        threadIndex = 1062
        threadHdr = {<nsCOMPtr_base> = {mRawPtr = 
    0x7ffcfbc53ab0}, <No data fields>}
        rv = 0
        newKey = 225870
#9  0x00007ffd1884f1f4 in nsMsgQuickSearchDBView::OnNewHeader (this=

Seem like having a duplicate in Fedora bug 546865

This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux major release.  Product Management has requested further
review of this request by Red Hat Engineering, for potential inclusion in a Red
Hat Enterprise Linux Major release.  This request is not yet committed for
inclusion.

This issue has been proposed when we are only considering blocker
issues in the current Red Hat Enterprise Linux release. It has
been denied for the current Red Hat Enterprise Linux release.

** If you would still like this issue considered for the current
release, ask your support representative to file as a blocker on
your behalf. Otherwise ask that it be considered for the next
Red Hat Enterprise Linux release. **

This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated
in the current release, Red Hat is unfortunately unable to
address this request at this time. Red Hat invites you to
ask your support representative to propose this request, if
appropriate and relevant, in the next release of Red Hat
Enterprise Linux. If you would like it considered as an
exception in the current release, please ask your support
representative.

This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated
in the current release, Red Hat is unfortunately unable to
address this request at this time. Red Hat invites you to
ask your support representative to propose this request, if
appropriate and relevant, in the next release of Red Hat
Enterprise Linux. If you would like it considered as an
exception in the current release, please ask your support
representative.

This request was erroneously denied for the current release of
Red Hat Enterprise Linux.  The error has been fixed and this
request has been re-proposed for the current release.

Since RHEL 6.2 External Beta has begun, and this bug remains
unresolved, it has been rejected as it is not proposed as
exception or blocker.

Red Hat invites you to ask your support representative to
propose this request, if appropriate and relevant, in the
next release of Red Hat Enterprise Linux.

Can you reproduce this bug by any chance lately?

I haven't seen it lately (now on thunderbird-10.0.1-3.el6_2.x86_64)

It seems that this bug is not recurring lately. Closing as currentrelease.