Handle newlines in inline editor by escaping them as '\n'

app/display/editor/src/main/java/org/csstudio/display/builder/editor/tracker/SelectedWidgetUITracker.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2015-2020 Oak Ridge National Laboratory.
+ * Copyright (c) 2015-2024 Oak Ridge National Laboratory.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -14,6 +14,7 @@
 import java.util.Objects;
 import java.util.Optional;
 import java.util.concurrent.RecursiveTask;
+import java.util.concurrent.atomic.AtomicReference;
 import java.util.logging.Level;
 import java.util.stream.Collectors;
 
@@ -301,7 +302,8 @@ else if (widget instanceof GroupWidget)
 
         // Create text field, aligned with widget, but assert minimum size
         final MacroizedWidgetProperty<String> property = (MacroizedWidgetProperty<String>)check.get();
-        inline_editor = new TextField(property.getSpecification());
+        // Allow editing newlines as '\n'
+        inline_editor = new TextField(property.getSpecification().replace("\n", "\\n"));
         // 'Managed' text field would assume some default size,
         // but we set the exact size in here
         inline_editor.setManaged(false);
@@ -316,21 +318,27 @@ else if (widget instanceof GroupWidget)
             PVAutocompleteMenu.INSTANCE.attachField(inline_editor);
 
         // On enter or lost focus, update the property. On Escape, just close.
-        final ChangeListener<? super Boolean> focused_listener = (prop, old, focused) ->
+        // Using atomic ref as holder so that focused_listener can remove itself
+        final AtomicReference<ChangeListener<? super Boolean>> focused_listener = new AtomicReference<>();
+        focused_listener.set((prop, old, focused) ->
         {
             if (! focused)
             {
-                if (!property.getSpecification().equals(inline_editor.getText()))
-                    undo.execute(new SetMacroizedWidgetPropertyAction(property, inline_editor.getText()));
+                final String new_text = inline_editor.getText().replace("\\n", "\n");
+                if (!property.getSpecification().equals(new_text))
+                    undo.execute(new SetMacroizedWidgetPropertyAction(property, new_text));
+                inline_editor.focusedProperty().removeListener(focused_listener.get());
                 // Close when focus lost
                 closeInlineEditor();
             }
-        };
+        });
 
         inline_editor.setOnAction(event ->
         {
-            undo.execute(new SetMacroizedWidgetPropertyAction(property, inline_editor.getText()));
-            inline_editor.focusedProperty().removeListener(focused_listener);
+            final String new_text = inline_editor.getText().replace("\\n", "\n");
+            if (!property.getSpecification().equals(new_text))
+                undo.execute(new SetMacroizedWidgetPropertyAction(property, new_text));
+            inline_editor.focusedProperty().removeListener(focused_listener.get());
             closeInlineEditor();
         });
 
@@ -340,13 +348,13 @@ else if (widget instanceof GroupWidget)
             {
             case ESCAPE:
                 event.consume();
-                inline_editor.focusedProperty().removeListener(focused_listener);
+                inline_editor.focusedProperty().removeListener(focused_listener.get());
                 closeInlineEditor();
             default:
             }
         });
 
-        inline_editor.focusedProperty().addListener(focused_listener);
+        inline_editor.focusedProperty().addListener(focused_listener.get());
 
         inline_editor.selectAll();
         inline_editor.requestFocus();