Skyline version: 1.3.9.4037
Installation ID: 684929cd-7c0d-4047-850f-1be16d2a8d5b
Exception type: System.NullReferenceException
Error message: Object reference not set to an instance of an object.

Stack trace:
   at pwiz.Skyline.Model.Find.BookmarkEnumerator.set_Current(Bookmark value) in C:\proj\skyline_1_4_x64\pwiz_tools\Skyline\Model\Find\BookmarkEnumerator.cs:line 202
   at pwiz.Skyline.Model.Find.BookmarkEnumerator..ctor(SrmDocument document, Bookmark bookmark) in C:\proj\skyline_1_4_x64\pwiz_tools\Skyline\Model\Find\BookmarkEnumerator.cs:line 51
   at pwiz.Skyline.SkylineWindow.FindNext(Boolean reverse) in C:\proj\skyline_1_4_x64\pwiz_tools\Skyline\Skyline.cs:line 1444
   at pwiz.Skyline.EditUI.FindNodeDlg.FindNext() in C:\proj\skyline_1_4_x64\pwiz_tools\Skyline\EditUI\FindNodeDlg.cs:line 115
   at System.Windows.Forms.Button.PerformClick()
   at System.Windows.Forms.Form.ProcessDialogKey(Keys keyData)
   at System.Windows.Forms.Control.PreProcessMessage(Message& msg)
   at System.Windows.Forms.Control.PreProcessControlMessageInternal(Control target, Message& msg)
   at System.Windows.Forms.Application.ThreadContext.PreTranslateMessage(MSG& msg)

Checked in a fix to the 1.4 branch rev 4073.
It looked like this could happen if the SequenceTree said that the selected IdentityPath was null, so I made it so that the Bookmark class treats null as IdentityPath.ROOT.