Repro:

• start a conversation with another avatar

• "upgrade" the conversation to a conference

• right-click the IM well and pick "Close All"
  => crash

Call stack:

CatznipBeta.exe!LLError::crashAndLoop(...)
<boost snip>
CatznipBeta.exe!LLIMChiclet::getIMSessionType(const LLUUID & session_id)
CatznipBeta.exe!LLIMWellWindow::closeAllImpl()
CatznipBeta.exe!LLIMWellWindow::closeAll()
CatznipBeta.exe!LLIMWellChiclet::onMenuItemClicked(const LLSD & user_data)
<boost snip>
CatznipBeta.exe!LLUICtrl::onCommit()

Cause: when the session id is updated, the object IM row's value is updated but the embedded chiclet's isn't and it's that session id that is ultimately used in closeConversation

Minidumps:

• CatznipBeta-9.0.9.34252!14276654 (2)