Comment 6 for bug 361170

I can confirm that this is due to Library sorting. It looks like some really dismal performance with sorting.

Here is a backtrace from a screen freeze:

Thread 1 (Thread 0xb60f0930 (LWP 23733)):
#0 0xb6b2e4f5 in QMutex::lock () from /usr/share/qt4/lib/libQtCore.so.4
---Type <return> to continue, or q <return> to quit---
#1 0xb6b71a7d in ?? () from /usr/share/qt4/lib/libQtCore.so.4
#2 0xb6b72465 in QRegExp::operator= () from /usr/share/qt4/lib/libQtCore.so.4
#3 0xb6b72625 in QRegExp::QRegExp () from /usr/share/qt4/lib/libQtCore.so.4
#4 0xb6b78f1c in QString::indexOf () from /usr/share/qt4/lib/libQtCore.so.4
#5 0x0816a491 in SortFilterProxyModel::lessThan (this=0xa0e0b58,
    left=@0xbfe7492c, right=@0xbfe7491c) at src/proxymodel.cpp:34