Fix #328: Settings > File Format Associations Dialog Issue

Author: Rpinski

src/AddIns/Misc/FiletypeRegisterer/Project/Src/RegisterFiletypesPanel.Designer.cs

@@ -80,5 +80,12 @@ public override bool StorePanelContents()
 			}
 			return true;
 		}
+		
+		void fileTypesListBox_MouseClick(object sender, System.Windows.Forms.MouseEventArgs e)
+		{
+			if (fileTypesListBox.IndexFromPoint(e.X, e.Y) == ListBox.NoMatches) {
+				fileTypesListBox.SelectedIndex = -1;
+			}
+		}
 	}
 }