Made several buttons non-focusable.

core/src/main/java/com/github/weisj/darklaf/ui/internalframe/DarkDesktopIconUI.java

@@ -55,6 +55,7 @@ public class DarkDesktopIconUI extends BasicDesktopIconUI {
 
         button = new JButtonUIResource(title, icon);
         button.setOpaque(false);
+        button.setFocusable(false);
         button.putClientProperty(DarkButtonUI.KEY_VARIANT, DarkButtonUI.VARIANT_FULL_SHADOW);
         button.putClientProperty(DarkButtonUI.KEY_HOVER_COLOR, UIManager.getColor("DesktopIcon.hoverColor"));
         button.putClientProperty(DarkButtonUI.KEY_CLICK_COLOR, UIManager.getColor("DesktopIcon.hoverColor"));

core/src/main/java/com/github/weisj/darklaf/ui/tabbedpane/MoreTabsButton.java

@@ -46,6 +46,7 @@ public class MoreTabsButton extends DarkTabAreaButton {
         setIcon(EmptyIcon.create(icon.getIconWidth(), icon.getIconHeight()));
         putClientProperty(DarkButtonUI.KEY_VARIANT, DarkButtonUI.VARIANT_ONLY_LABEL);
         putClientProperty(DarkButtonUI.KEY_SQUARE, true);
+        setFocusable(false);
         setFont(getFont().deriveFont(8f));
     }
 

core/src/main/java/com/github/weisj/darklaf/ui/tabbedpane/NewTabButton.java

@@ -52,6 +52,7 @@ public class NewTabButton extends JPanel implements UIResource {
     protected JButton createButton() {
         JButton button = new JButtonUIResource();
         button.setIcon(ui.getNewTabIcon());
+        button.setFocusable(false);
         button.putClientProperty(DarkButtonUI.KEY_VARIANT, DarkButtonUI.VARIANT_SHADOW);
         button.putClientProperty(DarkButtonUI.KEY_SQUARE, Boolean.TRUE);
         button.putClientProperty(DarkButtonUI.KEY_ALT_ARC, Boolean.TRUE);