Fix VeLa dialog scratch code not retained when closed without OK (#553)

Persist editor text to the static cache in dispose() so Cancel and window
close behave like dismiss, matching user expectation for the Tools -> VeLa
scratch buffer.

Made-with: Cursor

Author: dbenn

src/org/aavso/tools/vstar/ui/vela/VeLaDialog.java

@@ -178,10 +178,26 @@ protected JPanel createButtonPane() {
 
     @Override
     protected void okAction() {
-        VeLaDialog.code = VeLaDialog.codeTextArea.getValue();
         super.okAction();
     }
 
+    /**
+     * Retain VeLa source across dialog invocations whenever the window is closed
+     * (OK, Cancel, or window close), not only when the dismiss button runs
+     * {@link #okAction()}.
+     */
+    @Override
+    public void dispose() {
+        persistCodeFromEditor();
+        super.dispose();
+    }
+
+    private static void persistCodeFromEditor() {
+        if (codeTextArea != null) {
+            code = codeTextArea.getValue();
+        }
+    }
+
     private static void addKeyListener() {
         JTextArea area = (JTextArea) (codeTextArea.getUIComponent());
         area.addKeyListener(new KeyAdapter() {