Terminal: fix moving a terminal tab to another terminals view

terminal/bundles/org.eclipse.terminal.control/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.terminal.control; singleton:=true
-Bundle-Version: 1.1.200.qualifier
+Bundle-Version: 1.1.300.qualifier
 Bundle-Activator: org.eclipse.terminal.internal.control.impl.TerminalPlugin
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin

terminal/bundles/org.eclipse.terminal.control/src/org/eclipse/terminal/internal/emulator/VT100TerminalControl.java

@@ -657,9 +657,12 @@ public void setupTerminal(Composite parent) {
 		setupControls(parent);
 		setCommandInputField(fCommandInputField);
 		setupListeners();
-		if (fPreferenceStore != null && wasDisposed) {
+		if (fPreferenceStore != null) {
+			// new controls after a drag and drop need the colors and font as well
 			updatePreferences(null);
-			fPreferenceStore.addPropertyChangeListener(fPreferenceListener);
+			if (wasDisposed) {
+				fPreferenceStore.addPropertyChangeListener(fPreferenceListener);
+			}
 		}
 		JFaceResources.getFontRegistry().addListener(fFontListener);
 		setupHelp(fWndParent, TerminalPlugin.HELP_VIEW);
@@ -763,7 +766,10 @@ protected void setupControls(Composite parent) {
 		snapshot.updateSnapshot(false);
 		fPollingTextCanvasModel = new PollingTextCanvasModel(snapshot);
 		fCtlText = new TextCanvas(fWndParent, fPollingTextCanvasModel, SWT.NONE,
-				new TextLineRenderer(() -> fCtlText, fPollingTextCanvasModel));
+				// While the canvas is being created, fCtlText may still be the canvas disposed by a
+				// drag and drop to another tab folder: measure on the display then
+				new TextLineRenderer(() -> fCtlText != null && !fCtlText.isDisposed() ? fCtlText : null,
+						fPollingTextCanvasModel));
 
 		fCtlText.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
 		fCtlText.addResizeHandler((lines, columns) -> fTerminalText.setDimensions(lines, columns));

terminal/tests/org.eclipse.terminal.test/src/org/eclipse/terminal/internal/textcanvas/TerminalControlRecreateUITest.java

@@ -0,0 +1,94 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Eclipse contributors and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package org.eclipse.terminal.internal.textcanvas;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.eclipse.jface.preference.PreferenceStore;
+import org.eclipse.swt.graphics.RGB;
+import org.eclipse.swt.layout.FillLayout;
+import org.eclipse.swt.widgets.Composite;
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Shell;
+import org.eclipse.terminal.connector.ITerminalConnector;
+import org.eclipse.terminal.connector.TerminalState;
+import org.eclipse.terminal.control.ITerminalListener;
+import org.eclipse.terminal.control.TerminalTitleRequestor;
+import org.eclipse.terminal.internal.emulator.VT100TerminalControl;
+import org.eclipse.terminal.internal.preferences.ITerminalConstants;
+import org.eclipse.terminal.model.TerminalColor;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests recreating the terminal controls in a new parent, as moving a terminal tab to another
+ * terminals view does.
+ */
+public class TerminalControlRecreateUITest {
+
+	private static final RGB BACKGROUND = new RGB(1, 2, 3);
+
+	private Display display;
+	private Shell shell;
+	private VT100TerminalControl terminal;
+
+	@BeforeEach
+	public void createTerminal() {
+		display = Display.getCurrent() != null ? null : new Display();
+		shell = new Shell();
+		shell.setLayout(new FillLayout());
+		PreferenceStore preferences = new PreferenceStore();
+		preferences.setValue(ITerminalConstants.getPrefForTerminalColor(TerminalColor.BACKGROUND),
+				"1,2,3"); //$NON-NLS-1$
+		ITerminalListener listener = new ITerminalListener() {
+			@Override
+			public void setState(TerminalState state) {
+			}
+
+			@Override
+			public void setTerminalSelectionChanged() {
+			}
+
+			@Override
+			public void setTerminalTitle(String title, TerminalTitleRequestor requestor) {
+			}
+		};
+		terminal = new VT100TerminalControl(listener, new Composite(shell, 0), new ITerminalConnector[0], preferences);
+	}
+
+	@AfterEach
+	public void dispose() {
+		// as the terminals view does when a terminal tab is closed
+		terminal.disposeTerminal();
+		shell.dispose();
+		if (display != null) {
+			display.dispose();
+		}
+	}
+
+	private void recreateInNewParent() {
+		terminal.setupTerminal(new Composite(shell, 0));
+	}
+
+	@Test
+	public void recreatingDoesNotUseTheDisposedCanvas() {
+		assertDoesNotThrow(this::recreateInNewParent);
+	}
+
+	@Test
+	public void recreatedCanvasKeepsThePreferences() {
+		assertEquals(BACKGROUND, ((TextCanvas) terminal.getControl()).getCellRenderer().getDefaultBackgroundColor().getRGB());
+		recreateInNewParent();
+		assertEquals(BACKGROUND, ((TextCanvas) terminal.getControl()).getCellRenderer().getDefaultBackgroundColor().getRGB());
+	}
+}

terminal/tests/org.eclipse.terminal.test/src/org/eclipse/terminal/test/AutomatedTestSuite.java

@@ -25,6 +25,7 @@
 		org.eclipse.terminal.model.AllTestSuite.class, //
 		org.eclipse.terminal.internal.connector.TerminalConnectorTest.class, //
 		org.eclipse.terminal.internal.connector.TerminalToRemoteInjectionOutputStreamTest.class, //
+		org.eclipse.terminal.internal.textcanvas.TerminalControlRecreateUITest.class, //
 		org.eclipse.terminal.view.ui.tests.TerminalsViewReorderTest.class, //
 })
 public class AutomatedTestSuite {