Ensure JSpinner has the correct background when first installed.

core/src/main/java/com/github/weisj/darklaf/ui/spinner/DarkSpinnerListener.java

@@ -32,7 +32,6 @@ import java.beans.PropertyChangeListener;
 import javax.swing.*;
 
 import com.github.weisj.darklaf.util.PropertyKey;
-import com.github.weisj.darklaf.util.PropertyUtil;
 
 public class DarkSpinnerListener extends MouseAdapter
         implements PropertyChangeListener, FocusListener, SpinnerConstants {
@@ -94,7 +93,7 @@ public class DarkSpinnerListener extends MouseAdapter
             spinner.revalidate();
             spinner.repaint();
         } else if (PropertyKey.ENABLED.equals(key)) {
-            PropertyUtil.installBackground(spinner, spinner.isEnabled() ? ui.background : ui.inactiveBackground);
+            ui.updateBackground();
         }
     }
 }

core/src/main/java/com/github/weisj/darklaf/ui/spinner/DarkSpinnerUI.java

@@ -35,6 +35,7 @@ import com.github.weisj.darklaf.components.ArrowButton;
 import com.github.weisj.darklaf.delegate.LayoutManagerDelegate;
 import com.github.weisj.darklaf.graphics.PaintUtil;
 import com.github.weisj.darklaf.util.PropertyKey;
+import com.github.weisj.darklaf.util.PropertyUtil;
 
 /**
  * @author Konstantin Bulenkov
@@ -84,6 +85,7 @@ public class DarkSpinnerUI extends BasicSpinnerUI implements SpinnerConstants {
         arrowUpInactiveIcon = UIManager.getIcon("Spinner.arrowUpInactive.icon");
         minusInactiveIcon = UIManager.getIcon("Spinner.minusInactive.icon");
         plusInactiveIcon = UIManager.getIcon("Spinner.plusInactive.icon");
+        updateBackground();
         LookAndFeel.installProperty(spinner, PropertyKey.OPAQUE, false);
     }
 
@@ -241,7 +243,6 @@ public class DarkSpinnerUI extends BasicSpinnerUI implements SpinnerConstants {
         JComponent editor = spinner.getEditor();
 
         if (editorComponent != null) {
-            // System.out.println(((JComponent) editorComponent).getBorder());
             editorComponent.setBackground(getBackground(c));
             g.setColor(editorComponent.getBackground());
         } else {
@@ -282,6 +283,10 @@ public class DarkSpinnerUI extends BasicSpinnerUI implements SpinnerConstants {
         return c == null ? inactiveBackground : c.getBackground();
     }
 
+    protected void updateBackground() {
+        PropertyUtil.installBackground(spinner, spinner.isEnabled() ? background : inactiveBackground);
+    }
+
     protected Color getArrowBackground(final JComponent c) {
         return c == null || !c.isEnabled() ? inactiveBackground : arrowBackground;
     }

core/src/test/java/ui/spinner/SpinnerDemo.java

@@ -38,9 +38,15 @@ public class SpinnerDemo implements ComponentDemo {
 
     @Override
     public JComponent createComponent() {
-        JSpinner spinner = new JSpinner();
+        JSpinner spinner = new JSpinner() {
-        DemoPanel panel = new DemoPanel(spinner);
 
+            @Override
+            public void updateUI() {
+                super.updateUI();
+                ((JFormattedTextField) getEditor().getComponent(0)).setColumns(3);
+            }
+        };
+        DemoPanel panel = new DemoPanel(spinner);
         JPanel controlPanel = panel.addControls(1);
         controlPanel.add(new JCheckBox("enabled") {
             {