(In reply to Andreas Fetzer from comment #2)
I've tried to add m_ToolManager->ActivateTool(-1) at the end of the ConfirmSegmentation() method. This results in SIGSEGV after leaving this method in QmitkFastMarchingTool3DGUI::OnConfirmSegmentation().
[f94554]: Merge branch 'bug-16021-DeactivateFastMarchingAfterConfirm'
2013-11-08 16:25:17 Michael Brehler [e575d2]
now the gui is closed after confirming the segmentation