Fix #328: Settings > File Format Associations Dialog Issue

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

@@ -71,6 +71,7 @@ namespace ICSharpCode.FiletypeRegisterer
 			this.fileTypesListBox.Name = "fileTypesListBox";
 			this.fileTypesListBox.Size = new System.Drawing.Size(328, 299);
 			this.fileTypesListBox.TabIndex = 1;
+			this.fileTypesListBox.MouseClick += new System.Windows.Forms.MouseEventHandler(this.fileTypesListBox_MouseClick);
 			// 
 			// RegisterFiletypesPanel
 			// 
@@ -79,6 +80,7 @@ namespace ICSharpCode.FiletypeRegisterer
 			this.Name = "RegisterFiletypesPanel";
 			this.Size = new System.Drawing.Size(334, 328);
 			this.ResumeLayout(false);
+
 		}
 		private System.Windows.Forms.CheckedListBox fileTypesListBox;
 		private System.Windows.Forms.Label captionLabel;

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

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