If the floating tag editor panel is open, and a different tab is opened where the tag editor was left docked in the main panel. I get this error:
MusicBee v3.0.5917.40557 (Win6.1), 14 Mar 2016 20:26:
System.NullReferenceException: Object reference not set to an instance of an object.
at MusicBee.MusicBeeMain.#=qYB5Dp6yBOFelHmHovGOJOfE1KqUK4RKyS_OuOOsIiss=.#=qQYjt7FZ_wlzuD3UdKLDJzw==(Rectangle #=qFC28LNHKqiq1xehxInHqAQ==)
at MusicBee.MusicBeeMain.#=qC4eP2b12o8d6DpjfMs9CeHdmKabjVapKeNpHkgXm4vI=(#=qgcPo5BIYQ89M1VRBEhUpK957GTFBl8DKZLNZERt5diU= #=q5xgVKbNzm21baqnO1uJmvA==, Boolean #=qzal9cGfSYRUeRmKHMLaD_it5MObttkuhEucTiGl$o78=)
at MusicBee.MusicBeeMain.#=qgVgXtocKdlnBFnB$mDu$xw==(#=qgcPo5BIYQ89M1VRBEhUpK957GTFBl8DKZLNZERt5diU= #=q1WmP6cTjLADHotHk3Hf3zA==, Boolean #=qXRIryDnnQfzGTyerTuwEbd0Nsk0ACLYBLSHulGlCqLE=)
at MusicBee.MusicBeeMain.#=qwfoVvRaOxNaQwwcidIEMQARR2vmhNvL$s116xRmR9_A=()
at MusicBee.MusicBeeMain.NavigationHeader.#=qKeDWDme33MbYaaNdmnBzhQ==(Int32 #=qqMmCMGDiYsmoFznyPAp0NA==)
at MusicBee.MusicBeeMain.NavigationHeader.#=qJnHHqMldosd2sxQx$FozaQ==(MouseEventArgs #=q4i8X3w32TQp91ZHVGOE1kw==)
at MusicBee.MusicBeeMain.OnMouseClick(MouseEventArgs #=qKY913_gxgRoAAu42AsI8Qg==)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.Form.WndProc(Message& m)
at #=qz0DJW_iqhyi8DxNfTD84Li4p9ydBYP3$W0egkhEaaZU=.WndProc(Message& #=qlGT$CasTsogPtWh$iSyg2g==)
at MusicBee.MusicBeeMain.WndProc(Message& #=qMoOTTWEz1mdtJPL_85OqMg==)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)