Added a button & menu item for resetting the variable table to its default order (#1867)

* Added a button&menu item to reset var table to its default order

Added a button&menu item to reset var table to its default order.

* Updated the comment of the action of resetting var table sorting

Updated the comment of the action of resetting var table sorting

* Added a mnemonic key for resetting the var table to its default order

Added a mnemonic key for resetting the var table to its default order

trick_source/java/src/main/java/trick/tv/TVApplication.java

@@ -368,6 +368,18 @@ public class TVApplication extends RunTimeTrickApplication implements VariableLi
         }
     };
 
+    /** reset the variable table to its default order */
+    protected AbstractAction resetSortingAction = new AbstractAction("Reset Table Sorting",
+      new ImageIcon(TVApplication.class.getResource("resources/resetsorting.png"))) {
+        {
+        putValue(SHORT_DESCRIPTION, "Reset the variable table to its default order.");
+        putValue(MNEMONIC_KEY, KeyEvent.VK_B);
+        }
+        public void actionPerformed(ActionEvent actionEvent) {
+            variableTable.getRowSorter().setSortKeys(null);
+        }
+    };
+
     /** clear logs action */
     protected AbstractAction clearLogsAction = new AbstractAction("Clear All Logged Values") {
         {
@@ -1621,6 +1633,7 @@ public class TVApplication extends RunTimeTrickApplication implements VariableLi
             add(new JMenuItem(monitorAction));
             add(new JMenuItem(stripChartAction));
             add(new JMenuItem(removeAction));
+            add(new JMenuItem(resetSortingAction));
             add(new JMenuItem(clearLogsAction));
         }}, 1);
 
@@ -1679,6 +1692,7 @@ public class TVApplication extends RunTimeTrickApplication implements VariableLi
             add(Box.createHorizontalGlue());
             add(stripChartAction);
             add(removeAction);
+            add(resetSortingAction);
         }};
     }