Fix IndexOutOfBounds exceptions

src/main/java/org/jabref/gui/entryeditor/EntryEditor.java

@@ -89,7 +89,6 @@
 import com.google.common.eventbus.Subscribe;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.fxmisc.easybind.EasyBind;
 
 
 /**
@@ -180,8 +179,13 @@ public EntryEditor(BasePanel panel) {
         add(container, BorderLayout.CENTER);
 
         DefaultTaskExecutor.runInJavaFXThread(() -> {
-                    EasyBind.subscribe(tabbed.getSelectionModel().selectedItemProperty(), tab -> {
-                        EntryEditorTab activeTab = (EntryEditorTab) tab;
+            tabbed.getSelectionModel().selectedItemProperty().addListener((observable, oldTab, newTab) -> {
+                if (oldTab != null) {
+                    EntryEditorTab oldActiveTab = (EntryEditorTab) oldTab;
+                    oldActiveTab.notifyAboutFocusLost();
+                }
+
+                EntryEditorTab activeTab = (EntryEditorTab) newTab;
                         if (activeTab != null) {
                             activeTab.notifyAboutFocus(entry);
                         }

src/main/java/org/jabref/gui/entryeditor/EntryEditorTab.java

@@ -36,4 +36,11 @@ public void notifyAboutFocus(BibEntry entry) {
         }
         handleFocus();
     }
+
+    /**
+     * Notifies the tab that it lost focus and should clear all non-reusable content.
+     */
+    public void notifyAboutFocusLost() {
+
+    }
 }

src/main/java/org/jabref/gui/entryeditor/SourceTab.java

@@ -47,6 +47,7 @@ public class SourceTab extends EntryEditorTab {
     private UndoManager undoManager;
     private final ObjectProperty<ValidationMessage> sourceIsValid = new SimpleObjectProperty<>();
     private final ObservableRuleBasedValidator sourceValidator = new ObservableRuleBasedValidator(sourceIsValid);
+    private BindingsHelper.BidirectionalMapBinding<String, String, String> entryBinding;
 
     public SourceTab(BasePanel panel) {
         this.mode = panel.getBibDatabaseContext().getMode();
@@ -95,19 +96,36 @@ protected void bindToEntry(BibEntry entry) {
 
         // Store source for every change in the source code
         // and update source code for every change of entry field values
-        BindingsHelper.bindContentBidirectional(entry.getFieldsObservable(), codeArea.textProperty(), this::storeSource, fields -> {
-            DefaultTaskExecutor.runInJavaFXThread(() -> {
-                codeArea.clear();
-                try {
-                    codeArea.appendText(getSourceString(entry, mode));
-                } catch (IOException ex) {
-                    codeArea.setEditable(false);
-                    codeArea.appendText(ex.getMessage() + "\n\n" +
-                            Localization.lang("Correct the entry, and reopen editor to display/edit source."));
-                    LOGGER.debug("Incorrect entry", ex);
-                }
-            });
-        });
+        entryBinding = BindingsHelper.bindContentBidirectional(entry.getFieldsObservable(), codeArea.textProperty(), this::storeSource, fields ->
+                DefaultTaskExecutor.runInJavaFXThread(() -> {
+                    codeArea.clear();
+                    try {
+                        codeArea.appendText(getSourceString(entry, mode));
+                    } catch (IOException ex) {
+                        codeArea.setEditable(false);
+                        codeArea.appendText(ex.getMessage() + "\n\n" +
+                                Localization.lang("Correct the entry, and reopen editor to display/edit source."));
+                        LOGGER.debug("Incorrect entry", ex);
+                    }
+                }));
+    }
+
+    @Override
+    public void notifyAboutFocus(BibEntry entry) {
+        // Because we always clear the tab on focus lost (see notifyAboutFocusLost), we also have to always build it again
+        currentEntry = entry;
+        bindToEntry(entry);
+    }
+
+    @Override
+    public void notifyAboutFocusLost() {
+        if (currentEntry != null) {
+            currentEntry.getFieldsObservable().removeListener(entryBinding);
+        }
+
+        // Due to a bug in the source code editor (https://github.com/FXMisc/RichTextFX/issues/637), a hidden code editor makes troubles
+        // Thus, we just clear the source tab as soon as it losses focus
+        this.setContent(null);
     }
 
     private void storeSource(String text) {

src/main/java/org/jabref/gui/util/BindingsHelper.java

@@ -131,14 +131,16 @@ public static <A, B> void bindContentBidirectional(ListProperty<A> listProperty,
                 updateB);
     }
 
-    public static <A, V, B> void bindContentBidirectional(ObservableMap<A, V> propertyA, ObservableValue<B> propertyB, Consumer<B> updateA, Consumer<Map<A, V>> updateB) {
+    public static <A, V, B> BidirectionalMapBinding<A, V, B> bindContentBidirectional(ObservableMap<A, V> propertyA, ObservableValue<B> propertyB, Consumer<B> updateA, Consumer<Map<A, V>> updateB) {
         final BidirectionalMapBinding<A, V, B> binding = new BidirectionalMapBinding<>(propertyA, propertyB, updateA, updateB);
 
         // use list as initial source
         updateB.accept(propertyA);
 
         propertyA.addListener(binding);
         propertyB.addListener(binding);
+
+        return binding;
     }
 
     public static <A, V, B> void bindContentBidirectional(ObservableMap<A, V> propertyA, Property<B> propertyB, Consumer<B> updateA, Function<Map<A, V>, B> mapToB) {
@@ -231,15 +233,15 @@ public void onChanged(Change<? extends A> c) {
         }
     }
 
-    private static class BidirectionalMapBinding<A, V, B> implements MapChangeListener<A, V>, ChangeListener<B> {
+    public static class BidirectionalMapBinding<A, V, B> implements MapChangeListener<A, V>, ChangeListener<B> {
 
         private final ObservableMap<A, V> mapProperty;
         private final ObservableValue<B> property;
         private final Consumer<B> updateA;
         private final Consumer<Map<A, V>> updateB;
         private boolean updating = false;
 
-        public BidirectionalMapBinding(ObservableMap<A, V> mapProperty, ObservableValue<B> property, Consumer<B> updateA, Consumer<Map<A, V>> updateB) {
+        private BidirectionalMapBinding(ObservableMap<A, V> mapProperty, ObservableValue<B> property, Consumer<B> updateA, Consumer<Map<A, V>> updateB) {
             this.mapProperty = mapProperty;
             this.property = property;
             this.updateA = updateA;