panel splitter

src/main/java/cz/kamma/kfmanager/config/AppConfig.java

@@ -1001,4 +1001,13 @@ public class AppConfig {
             }
         }
     }
+
+    // --- Divider position persistence (split pane) ---
+    public double getDividerPosition() {
+        return Double.parseDouble(properties.getProperty("mainPanel.dividerPosition", "0.5"));
+    }
+
+    public void setDividerPosition(double position) {
+        properties.setProperty("mainPanel.dividerPosition", String.valueOf(position));
+    }
 }

src/main/java/cz/kamma/kfmanager/ui/MainWindow.java

@@ -26,6 +26,8 @@ public class MainWindow extends JFrame {
     private FilePanel leftPanel;
     private FilePanel rightPanel;
     private FilePanel activePanel;
+    private JSplitPane mainPanel;
+    private JLabel dividerStatusLabel;
     private JPanel buttonPanel;
     private JToolBar toolBar;
     private JComboBox<String> commandLine;
@@ -104,8 +106,9 @@ public class MainWindow extends JFrame {
         // Toolbar
         createToolBar();
         
-    // Panel containing the two file panels
+    // Panel containing the two file panels with resizable divider
-        JPanel mainPanel = new JPanel(new GridLayout(1, 2, 5, 0));
+        mainPanel = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT);
+        mainPanel.setContinuousLayout(true);
         
     // Left panel - load path and ViewMode from configuration
         String leftPath = config.getLeftPanelPath();
@@ -151,8 +154,50 @@ public class MainWindow extends JFrame {
             // Default value FULL is already set
         }
         
-        mainPanel.add(leftPanel);
+        mainPanel.setLeftComponent(leftPanel);
-        mainPanel.add(rightPanel);
+        mainPanel.setRightComponent(rightPanel);
+        
+        // Restore divider position from configuration
+        SwingUtilities.invokeLater(() -> {
+            double savedPosition = config.getDividerPosition();
+            if (savedPosition >= 0.0 && savedPosition <= 1.0) {
+                mainPanel.setDividerLocation(savedPosition);
+            } else {
+                // If it was saved as absolute pixels (historically), use as int
+                mainPanel.setDividerLocation((int) savedPosition);
+            }
+            updateDividerTooltip(mainPanel);
+        });
+        
+        mainPanel.setOneTouchExpandable(true);
+        updateDividerTooltip(mainPanel);
+        
+        // Listen for divider position changes to update saved position and tooltip
+        mainPanel.addPropertyChangeListener(JSplitPane.DIVIDER_LOCATION_PROPERTY, e -> {
+            int location = mainPanel.getDividerLocation();
+            int width = mainPanel.getWidth();
+            int dividerSize = mainPanel.getDividerSize();
+            if (width > dividerSize) {
+                double proportionalPosition = (double) location / (width - dividerSize);
+                config.setDividerPosition(proportionalPosition);
+            }
+            updateDividerTooltip(mainPanel);
+            
+            // Immediately show tooltip during drag if possible
+            for (Component c : mainPanel.getComponents()) {
+                if (c != mainPanel.getLeftComponent() && c != mainPanel.getRightComponent() && c instanceof JComponent) {
+                    MouseEvent postEvent = new MouseEvent(c, MouseEvent.MOUSE_MOVED, System.currentTimeMillis(), 0, 0, 0, 0, false);
+                    ToolTipManager.sharedInstance().mouseMoved(postEvent);
+                }
+            }
+        });
+        
+        mainPanel.addComponentListener(new java.awt.event.ComponentAdapter() {
+            @Override
+            public void componentResized(java.awt.event.ComponentEvent e) {
+                updateDividerTooltip(mainPanel);
+            }
+        });
         
         add(mainPanel, BorderLayout.CENTER);
         
@@ -382,6 +427,17 @@ public class MainWindow extends JFrame {
         
         cmdPanel.add(commandLine, BorderLayout.CENTER);
         
+        dividerStatusLabel = new JLabel("");
+        dividerStatusLabel.setFont(new Font("Monospaced", Font.BOLD, 13));
+        dividerStatusLabel.setForeground(Color.WHITE);
+        dividerStatusLabel.setBackground(new Color(0, 120, 215)); 
+        dividerStatusLabel.setOpaque(true);
+        dividerStatusLabel.setBorder(BorderFactory.createCompoundBorder(
+            BorderFactory.createLineBorder(new Color(0, 90, 160)),
+            BorderFactory.createEmptyBorder(2, 10, 2, 10)
+        ));
+        cmdPanel.add(dividerStatusLabel, BorderLayout.EAST);
+        
         // Load history from config
         java.util.List<String> history = config.getCommandLineHistory();
         for (int i = 0; i < history.size(); i++) {
@@ -2851,6 +2907,129 @@ public class MainWindow extends JFrame {
         if (rightPanel != null) rightPanel.showDrivePopup();
     }
     
+    /**
+     * Update divider tooltip with percentage sizes
+     */
+    private void updateDividerTooltip(JSplitPane splitPane) {
+        if (splitPane == null) return;
+        
+        // Get divider location in pixels
+        int location = splitPane.getDividerLocation();
+        int totalSize = splitPane.getOrientation() == JSplitPane.HORIZONTAL_SPLIT ? 
+                        splitPane.getWidth() : splitPane.getHeight();
+        int dividerSize = splitPane.getDividerSize();
+        int max = totalSize - dividerSize;
+        
+        if (max > 0) {
+            double proportionalPosition = (double) location / max;
+            // Calculate percentages
+            int leftPercent = (int) Math.round(proportionalPosition * 100);
+            int rightPercent = 100 - leftPercent;
+            
+            String firstLabel = splitPane.getOrientation() == JSplitPane.HORIZONTAL_SPLIT ? "Left" : "Top";
+            String secondLabel = splitPane.getOrientation() == JSplitPane.HORIZONTAL_SPLIT ? "Right" : "Bottom";
+            
+            String tooltip = String.format("%s: %d%% | %s: %d%%", firstLabel, leftPercent, secondLabel, rightPercent);
+            splitPane.setToolTipText(tooltip);
+            if (dividerStatusLabel != null) {
+                dividerStatusLabel.setText(String.format("%d%% : %d%%", leftPercent, rightPercent));
+                dividerStatusLabel.setToolTipText(tooltip);
+            }
+            
+            // Set tooltip also on the divider component itself
+            Component left = splitPane.getLeftComponent();
+            Component right = splitPane.getRightComponent();
+            for (Component c : splitPane.getComponents()) {
+                if (c != left && c != right) {
+                    if (c instanceof JComponent jc) {
+                        jc.setToolTipText(tooltip);
+                        ToolTipManager.sharedInstance().registerComponent(jc);
+                    }
+                    
+                    // Add mouse listener to the divider if not already present
+                    boolean hasListener = false;
+                    for (MouseMotionListener ml : c.getMouseMotionListeners()) {
+                        if (ml instanceof DividerMouseHandler) {
+                            hasListener = true;
+                            ((DividerMouseHandler)ml).updateTooltip(tooltip);
+                            break;
+                        }
+                    }
+                    
+                    if (!hasListener) {
+                        DividerMouseHandler handler = new DividerMouseHandler(splitPane, tooltip);
+                        c.addMouseListener(handler);
+                        c.addMouseMotionListener(handler);
+                    }
+                }
+            }
+        }
+    }
+
+    private class DividerMouseHandler extends MouseAdapter {
+        private final JSplitPane splitPane;
+        private String currentTooltip;
+        private JWindow tooltipWindow;
+        private JLabel tipLabel;
+
+        public DividerMouseHandler(JSplitPane splitPane, String tooltip) {
+            this.splitPane = splitPane;
+            this.currentTooltip = tooltip;
+            
+            tooltipWindow = new JWindow();
+            tipLabel = new JLabel();
+            tipLabel.setFont(new Font("SansSerif", Font.BOLD, 14));
+            tipLabel.setBorder(BorderFactory.createEmptyBorder(5, 12, 5, 12));
+            tipLabel.setBackground(new Color(40, 40, 40)); // Very dark gray
+            tipLabel.setForeground(Color.WHITE);
+            tipLabel.setOpaque(true);
+            tooltipWindow.add(tipLabel);
+            tooltipWindow.pack();
+            tooltipWindow.setAlwaysOnTop(true);
+        }
+
+        public void updateTooltip(String tooltip) {
+            this.currentTooltip = tooltip;
+            if (tipLabel != null) {
+                tipLabel.setText(tooltip);
+                tooltipWindow.pack();
+            }
+        }
+
+        @Override
+        public void mouseEntered(MouseEvent e) {
+            showWindow(e);
+        }
+
+        @Override
+        public void mouseExited(MouseEvent e) {
+            tooltipWindow.setVisible(false);
+        }
+
+        @Override
+        public void mouseMoved(MouseEvent e) {
+            updateLocation(e);
+        }
+
+        @Override
+        public void mouseDragged(MouseEvent e) {
+            updateLocation(e);
+            updateDividerTooltip(splitPane);
+        }
+
+        private void showWindow(MouseEvent e) {
+            tipLabel.setText(currentTooltip);
+            tooltipWindow.pack();
+            updateLocation(e);
+            tooltipWindow.setVisible(true);
+        }
+
+        private void updateLocation(MouseEvent e) {
+            Point p = e.getLocationOnScreen();
+            tooltipWindow.setLocation(p.x + 15, p.y + 15);
+        }
+    }
+    
     /**
      * Save configuration and exit application
      */