Added a per-tree wide selection setting

flatlaf-extras/src/main/java/com/formdev/flatlaf/extras/components/FlatTree.java

@@ -0,0 +1,28 @@
+package com.formdev.flatlaf.extras.components;
+
+import javax.swing.*;
+import static com.formdev.flatlaf.FlatClientProperties.TREE_WIDE_SELECTION;
+import static com.formdev.flatlaf.FlatClientProperties.clientPropertyBoolean;
+
+/**
+ * Subclass of {@link JTree} that provides easy access to FlatLaf specific client properties.
+ *
+ */
+public class FlatTree
+	extends JTree
+	implements FlatComponentExtension
+{
+	/**
+	 * Returns if the tree shows a wide selection
+	 */
+	public boolean isWideSelection() {
+		return clientPropertyBoolean( this, TREE_WIDE_SELECTION, UIManager.getBoolean( "Tree.wideSelection" ));
+	}
+
+	/**
+	 * Sets if the tree shows a wide selection
+	 */
+	public void setWideSelection(boolean wideSelection) {
+		putClientProperty( TREE_WIDE_SELECTION, wideSelection);
+	}
+}