The dialog box told me to post this, so I suppose this is the right thing to do.
Here is the report:
MusicBee v3.0.6067.36587 (Win6.1), 15 Oct 2016 15:52:
System.IndexOutOfRangeException: Index was outside the bounds of the array.
at #=qkXZ1f9ZgYZSbLb5OPlUOfY$nNcvUH_mqj3LW0D0aEC0=.#=q0izxfxSGkwsannXnxs8YC568W6nrHIdRKv9u4QY5$IM=.#=qJXKbdPpYrXhYqt6Dv58GZCCFekGAqT$po9hUsYld2U0=(Int32 #=qmGmiamx2Flg5heLz6ReJhA==, Int32 #=qRZGLgeOdT2d$q3ygFhwo2g==)
at #=qBu$wva79fxi$mJUtcqf7F9qXtCzaPDX35P_5il1Z$_k=.#=qseezGvF8efQfh0XHzB9lwvq53tqLEm06rdO6kzz4SL4=.#=qKxY0VBiWcPRw2K229ZjfVQ==()
at #=qBu$wva79fxi$mJUtcqf7F9qXtCzaPDX35P_5il1Z$_k=.#=qj6HqIZfuW8HIsA8pXeSG8A==.#=qBzwfl2B9oVQeq5snFtqraQ==(Boolean #=qv5SsvqAQ2oW$UktXVz9MKA==)
at #=qBu$wva79fxi$mJUtcqf7F9qXtCzaPDX35P_5il1Z$_k=.#=qj6HqIZfuW8HIsA8pXeSG8A==.#=qRg0wRNhm_Gt8uspsEPWZ48L2Gk1SccOaJq_XCoDnelw=(Object #=qsG5fXNsjDH6Kn4cZF1XFrw==, EventArgs #=qTshZbCc3_z8oF2cTn8tA1A==)
at #=qtIFtOW4$6zgWFqGj42vmrSZI$3W2US1cFAguMcXDJcw=.OnLeave(EventArgs #=qaaosXe1oT_ThDPXxdNikiQ==)
at System.Windows.Forms.Control.NotifyLeave()
at System.Windows.Forms.ContainerControl.UpdateFocusedControl()
I noticed no differences when this appeared but it is a bug I think? Maybe you guys need it to make the app better se here it is.