Codepage, ECL, and some UI updates

j3270/src/main/java/haus/nightmare/j3270/ui/StatusBar.java

@@ -357,9 +357,12 @@ public class StatusBar extends JPanel {
             wordWrapStatus.setText("");
         }
 
-        // Field status: Numeric vs Alphanumeric
+        // Field status: Numeric vs Alphanumeric vs DBCS
         if (state.isFullSession() && client.getScreenBuffer().isFormatted()) {
-            if (client.getOIA().isNumeric()) {
+            if (client.getOIA().isDBCS()) {
+                fieldTypeStatus.setText("DBCS");
+                fieldTypeStatus.setForeground(ThemeManager.getOiaStatusSysAvail(theme));
+            } else if (client.getOIA().isNumeric()) {
                 fieldTypeStatus.setText("NUM");
                 fieldTypeStatus.setForeground(ThemeManager.getOiaFgWarn(theme));
             } else {

j3270/src/main/java/haus/nightmare/j3270/ui/TerminalPanel.java

@@ -10,6 +10,12 @@ import javax.swing.*;
 import java.awt.*;
 import java.awt.datatransfer.*;
 import java.awt.event.*;
+import java.awt.event.InputMethodEvent;
+import java.awt.event.InputMethodListener;
+import java.awt.font.TextHitInfo;
+import java.awt.im.InputMethodRequests;
+import java.text.AttributedCharacterIterator;
+import java.text.CharacterIterator;
 
 import static haus.nightmare.lib3270j.protocol.DS3270Constants.*;
 
@@ -18,7 +24,8 @@ import static haus.nightmare.lib3270j.protocol.DS3270Constants.*;
  * Supports colors, bold, underline, reverse, blink, GOCA vector graphics,
  * programmed symbols, search highlighting, and all 3278/3279 attributes.
  */
-public class TerminalPanel extends JPanel implements java.awt.print.Printable {
+public class TerminalPanel extends JPanel implements java.awt.print.Printable, InputMethodListener, InputMethodRequests {
+
 
     private Telnet3270Client client;
 
@@ -216,6 +223,10 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
         String cStyle = haus.nightmare.j3270.config.Settings.getCursorStyle();
         cursorStyle = "UNDERLINE".equalsIgnoreCase(cStyle) ? CursorStyle.UNDERLINE : CursorStyle.BLOCK;
 
+        enableInputMethods(true);
+        addInputMethodListener(this);
+
+
         // Handle mouse clicks to position cursor, selection, and grab focus
         MouseAdapter mouseHandler = new MouseAdapter() {
             @Override
@@ -715,6 +726,14 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
         repaint();
     }
 
+    public void select(int startRow, int startCol, int endRow, int endCol) {
+        selectionStartRow = startRow;
+        selectionStartCol = startCol;
+        selectionEndRow = endRow;
+        selectionEndCol = endCol;
+        repaint();
+    }
+
     public boolean hasSelection() {
         return selectionStartRow >= 0 && selectionEndRow >= 0 &&
                !(selectionStartRow == selectionEndRow && selectionStartCol == selectionEndCol);
@@ -740,11 +759,23 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
                 for (int c = c1; c <= c2; c++) {
                     int baddr = r * cols + c;
                     ExtendedAttribute ea = sb.getCell(baddr);
-                    char ch = ea.ucs4;
-                    if (ea.isFieldAttribute() || ch <= 0x20 || ch == 0xFF) {
+                    if (ea.isFieldAttribute()) {
+                        line.append(' ');
+                    } else if (ea.db == ExtendedAttribute.DB_RIGHT) {
+                        if (c > c1) {
+                            continue; // Character already added by DB_LEFT
+                        } else {
+                            line.append(' ');
+                        }
+                    } else if (ea.db == ExtendedAttribute.DB_SO || ea.db == ExtendedAttribute.DB_SI) {
                         line.append(' ');
                     } else {
-                        line.append(ch);
+                        char ch = ea.ucs4;
+                        if (ch <= 0x20 || ch == 0xFF) {
+                            line.append(' ');
+                        } else {
+                            line.append(ch);
+                        }
                     }
                 }
                 // Trim trailing whitespace on copied lines per HoD CutPasteOptions
@@ -782,11 +813,23 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
                     prevRow = curRow;
                 }
                 ExtendedAttribute ea = sb.getCell(addr);
-                char ch = ea.ucs4;
-                if (ea.isFieldAttribute() || ch <= 0x20 || ch == 0xFF) {
+                if (ea.isFieldAttribute()) {
+                    line.append(' ');
+                } else if (ea.db == ExtendedAttribute.DB_RIGHT) {
+                    if (addr > startAddr) {
+                        continue; // Character already added by DB_LEFT
+                    } else {
+                        line.append(' ');
+                    }
+                } else if (ea.db == ExtendedAttribute.DB_SO || ea.db == ExtendedAttribute.DB_SI) {
                     line.append(' ');
                 } else {
-                    line.append(ch);
+                    char ch = ea.ucs4;
+                    if (ch <= 0x20 || ch == 0xFF) {
+                        line.append(' ');
+                    } else {
+                        line.append(ch);
+                    }
                 }
             }
             int end = line.length();
@@ -2099,13 +2142,16 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
                     continue;
                 }
 
+                byte tr = ea.tr != 0 ? ea.tr : (currentFieldEa != null ? currentFieldEa.tr : 0);
+                boolean isOpaque = ((tr & 0xFF) == XAT_OPAQUE);
+
                 if (reverse) {
                     Color tmp = fgColor;
                     fgColor = (rawBg == 0) ? this.bgColor : bgColor;
                     bgColor = tmp;
                     g2.setColor(bgColor);
                     g2.fillRect(x, y, cellWidth, cellHeight);
-                } else if (bgIsExplicit || !bgColor.equals(this.bgColor)) {
+                } else if (isOpaque || bgIsExplicit || !bgColor.equals(this.bgColor)) {
                     g2.setColor(bgColor);
                     g2.fillRect(x, y, cellWidth, cellHeight);
                 }
@@ -2120,7 +2166,7 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
                 if (cs >= 0x40 && client.getProgramSymbolManager() != null && !suppressGlyph) {
                     haus.nightmare.lib3270j.graphics.ProgramSymbolSet.SymbolSlot slot = client.getProgramSymbolManager().getSymbol(cs, ea.ec & 0xFF);
                     if (slot != null) {
-                        int symBg = (bgIsExplicit || reverse) ? bgColor.getRGB() : 0;
+                        int symBg = (bgIsExplicit || reverse || isOpaque) ? bgColor.getRGB() : 0;
                         haus.nightmare.lib3270j.graphics.PixelBuffer symPb = slot.getScaledPixelBuffer(cellWidth, cellHeight, fgColor.getRGB(), symBg);
                         java.awt.image.BufferedImage img = AwtPixelBufferBridge.toBufferedImage(symPb);
                         if (img != null) {
@@ -2130,7 +2176,8 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
                     }
                 }
 
-                if (!drawnAsPs && !suppressGlyph) {
+                if (!drawnAsPs && !suppressGlyph && ea.db != ExtendedAttribute.DB_RIGHT
+                        && ea.db != ExtendedAttribute.DB_SO && ea.db != ExtendedAttribute.DB_SI) {
                     char ch = ea.ucs4;
                     if (ch > 0x20 && ch != 0xFF) {
                         Font f = bold ? boldTerminalFont : terminalFont;
@@ -2269,11 +2316,17 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
             boolean isUnderline = (cursorStyle == CursorStyle.UNDERLINE) ||
                                   (client.getInputProcessor() != null && client.getInputProcessor().isInsertMode());
             g2.setColor(CURSOR_COLOR);
+            ExtendedAttribute curEa = (curAddr >= 0 && curAddr < sb.getSize()) ? sb.getDisplayCell(curAddr) : null;
+            boolean isDbcs = curEa != null && (curEa.db == ExtendedAttribute.DB_LEFT || curEa.db == ExtendedAttribute.DB_RIGHT);
+            int cWidth = isDbcs ? (cellWidth * 2) : cellWidth;
+            if (isDbcs && curEa.db == ExtendedAttribute.DB_RIGHT && curCol > 0) {
+                cx -= cellWidth;
+            }
             if (isUnderline) {
                 int ulH = Math.max(2, cellHeight / 6);
-                g2.fillRect(cx, cy + cellHeight - ulH, cellWidth, ulH);
+                g2.fillRect(cx, cy + cellHeight - ulH, cWidth, ulH);
             } else {
-                g2.fillRect(cx, cy, cellWidth, cellHeight);
+                g2.fillRect(cx, cy, cWidth, cellHeight);
             }
         }
     }
@@ -2462,4 +2515,90 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
         paint(g2d);
         return PAGE_EXISTS;
     }
+
+    // =========================================================================
+    // Java Input Method Framework (IMF / IME) Support
+    // =========================================================================
+
+    @Override
+    public InputMethodRequests getInputMethodRequests() {
+        return this;
+    }
+
+    @Override
+    public void inputMethodTextChanged(InputMethodEvent event) {
+        if (client == null || !client.getConnectionState().isFullSession()) {
+            event.consume();
+            return;
+        }
+        AttributedCharacterIterator text = event.getText();
+        if (text != null) {
+            int committedCount = event.getCommittedCharacterCount();
+            char c = text.first();
+            for (int i = 0; i < committedCount && c != CharacterIterator.DONE; i++) {
+                client.typeCharacter(c);
+                c = text.next();
+            }
+            refreshScreen();
+        }
+        event.consume();
+    }
+
+    @Override
+    public void caretPositionChanged(InputMethodEvent event) {
+        // No-op
+    }
+
+    @Override
+    public Rectangle getTextLocation(TextHitInfo offset) {
+        Point p;
+        try {
+            p = getLocationOnScreen();
+        } catch (IllegalComponentStateException e) {
+            p = new Point(0, 0);
+        }
+        int curRow = 0, curCol = 0;
+        if (client != null && client.getScreenBuffer() != null) {
+            int cols = client.getScreenBuffer().getCols();
+            int curAddr = client.getScreenBuffer().getDisplayCursorAddress();
+            if (cols > 0) {
+                curRow = curAddr / cols;
+                curCol = curAddr % cols;
+            }
+        }
+        int cx = p.x + getRenderOffsetX() + curCol * cellWidth;
+        int cy = p.y + getRenderOffsetY() + curRow * cellHeight;
+        return new Rectangle(cx, cy, cellWidth, cellHeight);
+    }
+
+    @Override
+    public TextHitInfo getLocationOffset(int x, int y) {
+        return TextHitInfo.leading(0);
+    }
+
+    @Override
+    public int getInsertPositionOffset() {
+        return 0;
+    }
+
+    @Override
+    public AttributedCharacterIterator getCommittedText(int beginIndex, int endIndex, AttributedCharacterIterator.Attribute[] attributes) {
+        return null;
+    }
+
+    @Override
+    public int getCommittedTextLength() {
+        return 0;
+    }
+
+    @Override
+    public AttributedCharacterIterator cancelLatestCommittedText(AttributedCharacterIterator.Attribute[] attributes) {
+        return null;
+    }
+
+    @Override
+    public AttributedCharacterIterator getSelectedText(AttributedCharacterIterator.Attribute[] attributes) {
+        return null;
+    }
 }
+

j3270/src/test/java/haus/nightmare/j3270/ui/AutoConnectSettingsAndTerminalCenteringTest.java

@@ -0,0 +1,242 @@
+package haus.nightmare.j3270.ui;
+
+import haus.nightmare.j3270.J3270App;
+import haus.nightmare.j3270.config.Settings;
+import haus.nightmare.j3270.storage.HostStorage;
+import haus.nightmare.j3270.storage.SavedHost;
+import haus.nightmare.lib3270j.ConnectionConfig;
+import haus.nightmare.lib3270j.ConnectionState;
+import haus.nightmare.lib3270j.Telnet3270Client;
+import haus.nightmare.lib3270j.screen.ScreenBuffer;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import javax.swing.*;
+import java.awt.*;
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class AutoConnectSettingsAndTerminalCenteringTest {
+
+    private List<SavedHost> originalSavedHosts;
+    private Settings.StartupBehavior originalStartupBehavior;
+    private String originalAutoConnectHost;
+    private int originalAutoConnectPort;
+
+    @BeforeEach
+    public void setUp() {
+        originalSavedHosts = new ArrayList<>(HostStorage.getSavedHosts());
+        originalStartupBehavior = Settings.getStartupBehavior();
+        originalAutoConnectHost = Settings.getAutoConnectHost();
+        originalAutoConnectPort = Settings.getAutoConnectPort();
+    }
+
+    @AfterEach
+    public void tearDown() {
+        HostStorage.saveAll(originalSavedHosts);
+        Settings.setStartupBehavior(originalStartupBehavior);
+        Settings.setAutoConnectHost(originalAutoConnectHost);
+        Settings.setAutoConnectPort(originalAutoConnectPort);
+    }
+
+    @Test
+    @DisplayName("TerminalPanel centering: left bound is flush when constrained, centered with left <= right when too big")
+    public void testTerminalPanelCenteringLogic() {
+        TerminalPanel panel = new TerminalPanel();
+        panel.cellWidth = 10;
+        panel.cellHeight = 20;
+
+        Telnet3270Client client = new Telnet3270Client(new ConnectionConfig("localhost", 23));
+        client.getTelnetFSM().setConnectionState(ConnectionState.CONNECTED_3270);
+        ScreenBuffer sb = client.getScreenBuffer();
+        sb.erase(false);
+        panel.setClient(client);
+
+        int cols = sb.getDisplayCols(); // 80
+        int rows = sb.getDisplayRows(); // 24
+        int gridW = cols * panel.cellWidth; // 800
+        int gridH = rows * panel.cellHeight; // 480
+
+        // 1. Panel is smaller than grid: left bound must be 0 (flush left cells), vertical must be 0
+        panel.setSize(gridW - 100, gridH - 50);
+        assertEquals(0, panel.getRenderOffsetX(), "Left bound should be 0 when window width is constrained");
+        assertEquals(0, panel.getRenderOffsetY(), "Top bound should be 0 when window height is constrained");
+
+        // 2. Panel exactly matches grid: offset must be 0
+        panel.setSize(gridW, gridH);
+        assertEquals(0, panel.getRenderOffsetX(), "Offset X must be 0 when width exactly matches grid");
+        assertEquals(0, panel.getRenderOffsetY(), "Offset Y must be 0 when height exactly matches grid");
+
+        // 3. Panel is larger with odd extra (extra = 7)
+        panel.setSize(gridW + 7, gridH + 11);
+        int ox = panel.getRenderOffsetX();
+        int leftSpace = ox;
+        int rightSpace = (gridW + 7) - (ox + gridW);
+        assertTrue(leftSpace <= rightSpace, "Left blank space (" + leftSpace + ") must be <= right space (" + rightSpace + ")");
+        assertEquals(3, leftSpace);
+        assertEquals(4, rightSpace);
+
+        int oy = panel.getRenderOffsetY();
+        int topSpace = oy;
+        int bottomSpace = (gridH + 11) - (oy + gridH);
+        assertTrue(topSpace <= bottomSpace, "Top space must be <= bottom space");
+        assertEquals(5, topSpace);
+        assertEquals(6, bottomSpace);
+
+        // 4. Panel is larger with even extra (extra = 6)
+        panel.setSize(gridW + 6, gridH + 8);
+        assertEquals(3, panel.getRenderOffsetX());
+        assertEquals(4, panel.getRenderOffsetY());
+
+        panel.dispose();
+    }
+
+    @Test
+    @DisplayName("guardedPack does not resize window when window is too small")
+    public void testGuardedPackDoesNotResizeWhenTooSmall() {
+        try {
+            JFrame frame = new JFrame();
+            TerminalPanel panel = new TerminalPanel();
+            panel.cellWidth = 10;
+            panel.cellHeight = 20;
+
+            Telnet3270Client client = new Telnet3270Client(new ConnectionConfig("localhost", 23));
+            client.getTelnetFSM().setConnectionState(ConnectionState.CONNECTED_3270);
+            panel.setClient(client);
+
+            frame.getContentPane().add(panel);
+            frame.setSize(400, 300);
+            frame.addNotify(); // makes frame displayable
+
+            // Set size explicitly smaller than preferred size (800+ x 480+)
+            frame.setSize(400, 300);
+            Dimension sizeBefore = frame.getSize();
+
+            // Run guardedPack
+            panel.guardedPack();
+
+            // Window should not have expanded
+            Dimension sizeAfter = frame.getSize();
+            assertEquals(sizeBefore.width, sizeAfter.width, "Window width should NOT be enlarged when too small");
+            assertEquals(sizeBefore.height, sizeAfter.height, "Window height should NOT be enlarged when too small");
+
+            frame.dispose();
+            panel.dispose();
+        } catch (HeadlessException ignored) {
+            // Environment without X display
+        }
+    }
+
+    @Test
+    @DisplayName("SettingsDialog Startup & Auto-Connect presents saved connections dropdown and updates auto-connect host")
+    public void testSettingsDialogSavedConnectionsDropdown() throws Exception {
+        SavedHost host1 = new SavedHost("id-test-1", "Host Alpha", "alpha.mainframe.test", 23, 2, 24, 80, "LU1", true, "TSO", false, true, true, "BOTH", "037", "NONE", "", 0, "", "");
+        SavedHost host2 = new SavedHost("id-test-2", "Host Beta", "beta.mainframe.test", 992, 4, 43, 80, "LU2", false, "VM", true, false, true, "BOTH", "037", "NONE", "", 0, "", "");
+
+        List<SavedHost> testHosts = new ArrayList<>();
+        testHosts.add(host1);
+        testHosts.add(host2);
+        HostStorage.saveAll(testHosts);
+        Settings.setStartupBehavior(Settings.StartupBehavior.AUTO_CONNECT);
+
+        J3270App app;
+        try {
+            app = new J3270App();
+        } catch (HeadlessException e) {
+            return;
+        }
+
+        try {
+            SettingsDialog dialog = new SettingsDialog(app);
+
+            JComboBox<SavedHost> combo = dialog.getSavedHostBox();
+            assertNotNull(combo, "savedHostBox should not be null");
+            assertEquals(2, combo.getItemCount(), "Dropdown should contain all saved hosts");
+
+            // Host Alpha was autoConnect=true, so it should be initially selected
+            SavedHost initialSel = (SavedHost) combo.getSelectedItem();
+            assertNotNull(initialSel);
+            assertEquals("id-test-1", initialSel.getId());
+
+            // Switch to Host Beta
+            combo.setSelectedIndex(1);
+
+            // Trigger applySettings via reflection
+            java.lang.reflect.Method applyMethod = SettingsDialog.class.getDeclaredMethod("applySettings");
+            applyMethod.setAccessible(true);
+            applyMethod.invoke(dialog);
+
+            // Verify Host Beta is now the auto-connect host
+            SavedHost auto = HostStorage.getAutoConnectHost();
+            assertNotNull(auto, "Auto-connect host should exist");
+            assertEquals("id-test-2", auto.getId());
+            assertEquals("Host Beta", auto.getName());
+            assertEquals("beta.mainframe.test", auto.getHost());
+            assertEquals(992, auto.getPort());
+
+            SavedHost loadedAlpha = HostStorage.findById("id-test-1");
+            assertNotNull(loadedAlpha);
+            assertFalse(loadedAlpha.isAutoConnect(), "Host Alpha should no longer have autoConnect = true");
+
+            // Verify Settings autoConnectHost/Port synchronized
+            assertEquals("beta.mainframe.test", Settings.getAutoConnectHost());
+            assertEquals(992, Settings.getAutoConnectPort());
+
+            // Switch startup behavior to SHOW_CONNECT and apply
+            Field sbField = SettingsDialog.class.getDeclaredField("startupBehaviorBox");
+            sbField.setAccessible(true);
+            @SuppressWarnings("unchecked")
+            JComboBox<Settings.StartupBehavior> sbBox = (JComboBox<Settings.StartupBehavior>) sbField.get(dialog);
+            sbBox.setSelectedItem(Settings.StartupBehavior.SHOW_CONNECT);
+
+            applyMethod.invoke(dialog);
+            assertNull(HostStorage.getAutoConnectHost(), "When startup behavior is SHOW_CONNECT, auto-connect host should be cleared");
+
+            dialog.dispose();
+            app.dispose();
+        } finally {
+            HostStorage.saveAll(originalSavedHosts);
+        }
+    }
+
+    @Test
+    @DisplayName("Window size is adjusted once on connect for selected model and left untouched on onScreenSizeChanged")
+    public void testWindowSizedOnceForModelAndNotOnScreenSizeChanged() {
+        try {
+            JFrame frame = new JFrame();
+            TerminalPanel panel = new TerminalPanel();
+            panel.cellWidth = 10;
+            panel.cellHeight = 20;
+
+            frame.getContentPane().add(panel);
+            frame.addNotify();
+
+            // Pack for Model 4 (43 rows, 80 cols)
+            panel.packForModel(43, 80);
+            Dimension model4Size = frame.getSize();
+            assertTrue(model4Size.height >= 43 * 20, "Height should accommodate 43 rows");
+            assertTrue(model4Size.width >= 80 * 10, "Width should accommodate 80 cols");
+
+            // Pack for Model 5 (27 rows, 132 cols)
+            panel.packForModel(27, 132);
+            Dimension model5Size = frame.getSize();
+            assertTrue(model5Size.width >= 132 * 10, "Width should accommodate 132 cols");
+
+            // Set custom size and verify guardedPack leaves the window alone
+            frame.setSize(600, 400);
+            Dimension fixedSize = frame.getSize();
+
+            panel.guardedPack();
+            assertEquals(fixedSize.width, frame.getWidth());
+            assertEquals(fixedSize.height, frame.getHeight());
+
+            frame.dispose();
+            panel.dispose();
+        } catch (HeadlessException ignored) {}
+    }
+}

j3270/src/test/java/haus/nightmare/j3270/ui/DBCSInputAndClipboardTest.java

@@ -0,0 +1,153 @@
+package haus.nightmare.j3270.ui;
+
+import haus.nightmare.lib3270j.ConnectionConfig;
+import haus.nightmare.lib3270j.ConnectionState;
+import haus.nightmare.lib3270j.Telnet3270Client;
+import haus.nightmare.lib3270j.input.InputProcessor;
+import haus.nightmare.lib3270j.screen.ExtendedAttribute;
+import haus.nightmare.lib3270j.screen.ScreenBuffer;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import java.awt.*;
+import java.awt.event.InputMethodEvent;
+import java.text.AttributedString;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class DBCSInputAndClipboardTest {
+
+    @Test
+    @DisplayName("Clipboard selection skips DB_RIGHT cells to avoid duplicating wide characters")
+    public void testDBCSClipboardCopyNoDoubling() {
+        TerminalPanel panel = new TerminalPanel();
+        panel.setSize(800, 600);
+
+        ConnectionConfig config = new ConnectionConfig("localhost", 23);
+        config.setCodePage("930");
+        Telnet3270Client client = new Telnet3270Client(config);
+        client.getTelnetFSM().setConnectionState(ConnectionState.CONNECTED_3270);
+
+        ScreenBuffer sb = client.getScreenBuffer();
+        sb.erase(false);
+
+        // Put a 2-cell DBCS character at cells 0 and 1, followed by SBCS 'A' at cell 2
+        ExtendedAttribute cell0 = sb.getCell(0);
+        cell0.db = ExtendedAttribute.DB_LEFT;
+        cell0.ucs4 = '\u3000';
+
+        ExtendedAttribute cell1 = sb.getCell(1);
+        cell1.db = ExtendedAttribute.DB_RIGHT;
+        cell1.ucs4 = '\u3000';
+
+        ExtendedAttribute cell2 = sb.getCell(2);
+        cell2.db = ExtendedAttribute.DB_NONE;
+        cell2.ucs4 = 'A';
+
+        panel.setClient(client);
+
+        // Stream selection covering cells 0..2 (row 0, col 0..2)
+        panel.select(0, 0, 0, 2);
+        String selected = panel.getSelectedText();
+
+        assertEquals("\u3000A", selected, "Stream selection must not duplicate the DBCS character");
+    }
+
+    @Test
+    @DisplayName("Block selection skips DB_RIGHT cells to avoid duplicating wide characters")
+    public void testDBCSBlockSelectionNoDoubling() {
+        TerminalPanel panel = new TerminalPanel();
+        panel.setSize(800, 600);
+        panel.setBlockSelectMode(true);
+
+        ConnectionConfig config = new ConnectionConfig("localhost", 23);
+        config.setCodePage("930");
+        Telnet3270Client client = new Telnet3270Client(config);
+        client.getTelnetFSM().setConnectionState(ConnectionState.CONNECTED_3270);
+
+        ScreenBuffer sb = client.getScreenBuffer();
+        sb.erase(false);
+
+        // Put a 2-cell DBCS character at cells 0 and 1, followed by SBCS 'B' at cell 2
+        ExtendedAttribute cell0 = sb.getCell(0);
+        cell0.db = ExtendedAttribute.DB_LEFT;
+        cell0.ucs4 = '\u3000';
+
+        ExtendedAttribute cell1 = sb.getCell(1);
+        cell1.db = ExtendedAttribute.DB_RIGHT;
+        cell1.ucs4 = '\u3000';
+
+        ExtendedAttribute cell2 = sb.getCell(2);
+        cell2.db = ExtendedAttribute.DB_NONE;
+        cell2.ucs4 = 'B';
+
+        panel.setClient(client);
+
+        panel.select(0, 0, 0, 2);
+        String selected = panel.getSelectedText();
+
+        assertEquals("\u3000B", selected, "Block selection must not duplicate the DBCS character");
+    }
+
+    @Test
+    @DisplayName("InputMethodRequests returns cursor bounds and processes committed text")
+    public void testDBCSInputMethodRequestsAndEvents() {
+        TerminalPanel panel = new TerminalPanel();
+        panel.setSize(800, 600);
+
+        ConnectionConfig config = new ConnectionConfig("localhost", 23);
+        config.setCodePage("930");
+        Telnet3270Client client = new Telnet3270Client(config);
+        client.getTelnetFSM().setConnectionState(ConnectionState.CONNECTED_3270);
+
+        panel.setClient(client);
+
+        assertNotNull(panel.getInputMethodRequests(), "getInputMethodRequests must return this");
+
+        Rectangle loc = panel.getTextLocation(null);
+        assertNotNull(loc, "Text location must not be null");
+        assertTrue(loc.width > 0, "Cursor width must be positive");
+        assertTrue(loc.height > 0, "Cursor height must be positive");
+
+        // Simulate committed IME text '\u3000'
+        AttributedString as = new AttributedString("\u3000");
+        InputMethodEvent imeEvent = new InputMethodEvent(panel, InputMethodEvent.INPUT_METHOD_TEXT_CHANGED,
+                as.getIterator(), 1, null, null);
+        panel.inputMethodTextChanged(imeEvent);
+
+        ScreenBuffer sb = client.getScreenBuffer();
+        assertEquals(ExtendedAttribute.DB_LEFT, sb.getCell(0).db);
+        assertEquals('\u3000', sb.getCell(0).ucs4);
+        assertEquals(ExtendedAttribute.DB_RIGHT, sb.getCell(1).db);
+        assertEquals('\u3000', sb.getCell(1).ucs4);
+        assertEquals(2, sb.getCursorAddress(), "Cursor should advance by 2 after typing 2-cell DBCS");
+    }
+
+    @Test
+    @DisplayName("InputProcessor backspace over DBCS character deletes both cells")
+    public void testInputProcessorDBCSTypingAndBackspace() {
+        ConnectionConfig config = new ConnectionConfig("localhost", 23);
+        config.setCodePage("930");
+        Telnet3270Client client = new Telnet3270Client(config);
+        client.getTelnetFSM().setConnectionState(ConnectionState.CONNECTED_3270);
+
+        InputProcessor input = client.getInputProcessor();
+        ScreenBuffer sb = client.getScreenBuffer();
+        sb.erase(false);
+        sb.setCursorAddress(0);
+
+        // Type DBCS character
+        input.typeCharacter('\u3000');
+        assertEquals(2, sb.getCursorAddress());
+        assertEquals(ExtendedAttribute.DB_LEFT, sb.getCell(0).db);
+        assertEquals(ExtendedAttribute.DB_RIGHT, sb.getCell(1).db);
+
+        // Backspace over DBCS character
+        input.backspace();
+        assertEquals(0, sb.getCursorAddress(), "Cursor should back up 2 cells");
+        assertEquals(0, sb.getCell(0).ucs4, "Cell 0 should be deleted (null)");
+        assertEquals(0, sb.getCell(1).ucs4, "Cell 1 should be deleted (null)");
+        assertEquals(ExtendedAttribute.DB_NONE, sb.getCell(0).db);
+        assertEquals(ExtendedAttribute.DB_NONE, sb.getCell(1).db);
+    }
+}