FormattedTextField: On Linux, fixed IllegalArgumentException: Invalid location if JFormattedTextField.setDocument() is invoked in a focus gained listener on that formatted text field. (issue #698)

CHANGELOG.md

@@ -30,6 +30,9 @@ FlatLaf Change Log
 - Native Windows libraries: Fixed crash when running in Java 8 and newer Java
   version is installed in `PATH` environment variable and using class
   `SystemInfo` before AWT initialization. (issue #673)
+- FormattedTextField: On Linux, fixed `IllegalArgumentException: Invalid
+  location` if `JFormattedTextField.setDocument()` is invoked in a focus gained
+  listener on that formatted text field. (issue #698)
 
 
 ## 3.1.1

flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatCaret.java

@@ -256,10 +256,14 @@ public class FlatCaret
 		// select all
 		if( c instanceof JFormattedTextField ) {
 			EventQueue.invokeLater( () -> {
-				if( getComponent() == null )
+				// Warning: do not use variables from outside of this runnable
+				//          because they may be out-of-date when this runnable is executed
+
+				JTextComponent c2 = getComponent();
+				if( c2 == null )
 					return; // was deinstalled
 
-				select( 0, doc.getLength() );
+				select( 0, c2.getDocument().getLength() );
 			} );
 		} else {
 			select( 0, doc.getLength() );