Fix animation bug on ojfx 13

Author: oowekyala

src/main/java/net/sourceforge/pmd/util/fxdesigner/app/services/ASTManagerImpl.java

@@ -96,6 +96,8 @@ public ASTManagerImpl(DesignerRoot owner) {
                       } catch (ParseAbortedException e) {
                           updated = null;
                           currentException.setValue(e);
+                      } catch (LinkageError e) {
+                          updated = null;
                       }
 
                       compilationUnit.setValue(updated);

src/main/java/net/sourceforge/pmd/util/fxdesigner/util/controls/MutableTabPane.java

@@ -199,6 +199,7 @@ public T addTabWithNewController() {
 
     public void addTabWithController(T controller) {
         Tab tab = tabMaker().apply(Objects.requireNonNull(controller));
+        Objects.requireNonNull(tab, "Null tab?");
         addTabAndFocus(tab);
     }
 

src/main/java/net/sourceforge/pmd/util/fxdesigner/util/controls/PopOverWrapper.java

@@ -84,12 +84,16 @@ private void preload(Supplier<PopOver> supplier) {
     public void doFirstLoad(Stage stage) {
         myPopover.ifPresent(pop -> {
             pop.setOpacity(0);
+            pop.setAnimated(false);
             pop.show(stage, 40000, 40000);
 
             EventStreams.eventsOf(pop, WindowEvent.WINDOW_HIDDEN)
                         .subscribeForOne(e -> pop.setOpacity(1));
 
-            Platform.runLater(pop::hide);
+            Platform.runLater(() -> {
+                pop.hide();
+                pop.setAnimated(true);
+            });
         });
     }