@Override
			public void layoutContainer( Container target ) {
				if( isFullWindowContent() ) {
					super.layoutContainer( target );
					return;
				}

				// compute available bounds
				Insets insets = target.getInsets();
				int x = insets.left;
				int y = insets.top;
				int w = target.getWidth() - insets.left - insets.right;
				int h = target.getHeight() - insets.top - insets.bottom;

				// compute widths
				int leftWidth = leftPanel.getPreferredSize().width;
				int buttonsWidth = buttonPanel.getPreferredSize().width;
				int titleWidth = w - leftWidth - buttonsWidth;
				int minTitleWidth = UIScale.scale( titleMinimumWidth );

				// increase minimum width if icon is shown besides the title
				Icon icon = titleLabel.getIcon();
				if( icon != null ) {
					Insets iconInsets = iconLabel.getInsets();
					int iconTextGap = titleLabel.getComponentOrientation().isLeftToRight() ? iconInsets.right : iconInsets.left;
					minTitleWidth += icon.getIconWidth() + iconTextGap;
				}

				// if title is too small, reduce width of buttons
				if( titleWidth < minTitleWidth ) {
					buttonsWidth = Math.max( buttonsWidth - (minTitleWidth - titleWidth), buttonPanel.getMinimumSize().width );
					titleWidth = w - leftWidth - buttonsWidth;
				}

				// if title is still too small, reduce width of left panel (icon and embedded menu bar)
				if( titleWidth < minTitleWidth ) {
					int minLeftWidth = iconLabel.isVisible()
						? iconLabel.getWidth() - iconLabel.getInsets().right
						: UIScale.scale( noIconLeftGap );
					leftWidth = Math.max( leftWidth - (minTitleWidth - titleWidth), minLeftWidth );
					titleWidth = w - leftWidth - buttonsWidth;
				}

				if( target.getComponentOrientation().isLeftToRight() ) {
					// left-to-right
					leftPanel.setBounds( x, y, leftWidth, h );
					titleLabel.setBounds( x + leftWidth, y, titleWidth, h );
					buttonPanel.setBounds( x + leftWidth + titleWidth, y, buttonsWidth, h );
				} else {
					// right-to-left
					buttonPanel.setBounds( x, y, buttonsWidth, h );
					titleLabel.setBounds( x + buttonsWidth, y, titleWidth, h );
					leftPanel.setBounds( x + buttonsWidth + titleWidth, y, leftWidth, h );
				}

				// If menu bar is embedded and contains a horizontal glue component,
				// then move the title label to the same location as the glue component
				// and give it the same width.
				// This allows placing any component on the trailing side of the title pane.
				JMenuBar menuBar = rootPane.getJMenuBar();
				if( hasVisibleEmbeddedMenuBar( menuBar ) ) {
					Component horizontalGlue = findHorizontalGlue( menuBar );
					if( horizontalGlue != null ) {
						Point glueLocation = SwingUtilities.convertPoint( horizontalGlue, 0, 0, titleLabel );
						titleLabel.setBounds( titleLabel.getX() + glueLocation.x, titleLabel.getY(),
							horizontalGlue.getWidth(), titleLabel.getHeight() );
					}
				}

				// clear hit-test cache
				lastCaptionHitTestTime = 0;
			}
This panel paint a border at the top of the window in fullWindowContent mode,
if FlatLaf window decorations are enabled.
Only used on Windows 10.
<p>
This panel is not a child of the title pane.
Instead it is added by FlatRootPaneUI to the layered pane at a layer over all other layers.
flatlaf-core/src/main/java/com/formdev/flatlaf/ui/FlatTitlePane.java