Fixed crash on double click of usage list item

Fix missing end message if continuous section.

PROMS/Volian.Controls.Library/DisplayLibDocs.cs

@@ -260,10 +260,13 @@ namespace Volian.Controls.Library
                 Application.DoEvents();
             }
         }
+		private bool _ProcessingSelectedValueChanged = false;
         private void listBoxUsages_SelectedValueChanged(object sender, EventArgs e)
         {
             if (!_InitializingLibDocList)
             {
+				if (_ProcessingSelectedValueChanged) return;
+				_ProcessingSelectedValueChanged = true;
                 if (listBoxUsages.SelectedIndex == -1) return;
                 DocumentInfo di = LibDocList[listBoxLibDocs.SelectedIndex];
                 // see if the library document actually has data - data migration may have created a 'null' content within the
@@ -274,6 +277,7 @@ namespace Volian.Controls.Library
                     return;
                 }
                 _DisplayTabControl.OpenItem(di.LibraryDocumentUsageList[listBoxUsages.SelectedIndex]);
+				_ProcessingSelectedValueChanged = false;
             }
         }
         #endregion