fix: concurrent modify exception (#19)

Author: vran-dev

app/src/main/java/cc/cc1234/app/controller/NodeViewController.java

@@ -165,9 +165,11 @@ private void registerTreeViewListener() {
         zkNodeTreeView.getSelectionModel()
                 .selectedItemProperty()
                 .addListener((observable, oldValue, newValue) -> {
-                    nodeAddViewController.hide();
-                    if (newValue != null) {
-                        nodeInfoViewController.show(nodeViewRightPane, newValue.getValue());
+                    synchronized (this) {
+                        nodeAddViewController.hide();
+                        if (newValue != null) {
+                            nodeInfoViewController.show(nodeViewRightPane, newValue.getValue());
+                        }
                     }
                 });
     }

app/src/main/resources/assets/style.css

@@ -549,7 +549,7 @@
     -fx-border-color: #a0a0a0;
     -fx-background-insets: 0;
     -fx-background-color: transparent, white, transparent, white;
-    -fx-border-width: 1 1 0 1;
+    -fx-border-width: 1 1 1 1;
     /*-fx-effect: dropshadow(three-pass-box, #8e8e8e, 10, 0.3, 2.2, 2.2);*/
 }