Crash in project view with custom filter

Steps to reproduce:

1. Open clear UGENE
2. Open any file, e.g.buchnera.gbk
4. Input any value in filter string, so no documents/objects are visible in project view
5. Close object view for buchnera.gbk
6. Open buchnera.gbk again -> UGENE says that the document is already in project
7. Click OK -> UGENE crashes

OS-Version: 6.1.7600 () 0x100-0x1
0x5fcd3fbc: (U2Gui.dll) ?highlightItem:ProjectTreeController:U2::QAEXPAVDocument:2::Z + 0xc
0x1356b8a: (ugeneui.exe) Some static function + 0xfbcd73a
0x1353514: (ugeneui.exe) Some static function + 0xfbca0c4
0x13732ed: (ugeneui.exe) Some static function + 0xfbe9e9d
0x607b8baf: (QtCore4.dll) QMetaObject::metacall
0x5febc63e: (QtGui4.dll) QAction::activate
0x60247e5b: (QtGui4.dll) QToolButton::nextCheckState
0x601a6ed9: (QtGui4.dll) QButtonGroup::setId
0x601a6ed9: (QtGui4.dll) QButtonGroup::setId