Stop Windows from beeping.

src/MainForm.ui.cs

@@ -392,6 +392,10 @@ public partial class MainForm : Form
         // check if we should apply the keypress to the search results
         if ( e.KeyCode == Keys.Escape ) {
             mSearchQuery.Text = "" ;
+            e.SuppressKeyPress = true ;
+            e.Handled = true ;
+        } else if ( e.KeyCode == Keys.Return ) {
+            e.SuppressKeyPress = true ;
             e.Handled = true ;
         } else if ( e.KeyCode == Keys.Left || e.KeyCode == Keys.Right ) {
             mSearchResults.Focus() ;