added context menu for adding entries in empty space of the entry table

src/main/java/cz/kamma/jkeepass/KeepassApp.java

@@ -396,6 +396,36 @@ public class KeepassApp extends JFrame {
         });
         JScrollPane tableScrollPane = new JScrollPane(entryTable);
 
+        // Add popup menu for empty space in table scrollpane
+        tableScrollPane.addMouseListener(new MouseAdapter() {
+            @Override
+            public void mousePressed(MouseEvent e) {
+                showEmptySpacePopupMenu(e);
+            }
+
+            @Override
+            public void mouseReleased(MouseEvent e) {
+                showEmptySpacePopupMenu(e);
+            }
+
+            private void showEmptySpacePopupMenu(MouseEvent e) {
+                if (!e.isPopupTrigger()) {
+                    return;
+                }
+                // Check if click is actually in empty space (not on a row)
+                int row = entryTable.rowAtPoint(e.getPoint());
+                if (row >= 0) {
+                    return; // Click is on a row, let the table's mouse listener handle it
+                }
+
+                JPopupMenu popup = new JPopupMenu();
+                JMenuItem addPop = new JMenuItem("Add Entry");
+                addPop.addActionListener(al -> addEntry());
+                popup.add(addPop);
+                popup.show(e.getComponent(), e.getX(), e.getY());
+            }
+        });
+
         // Right side: Table and Notes
         rightSplitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, tableScrollPane, notesScrollPane);
         int rightDivider = prefs.getInt(PREF_RIGHT_DIVIDER, 250);