diff --git a/sources/elementspanel.cpp b/sources/elementspanel.cpp
index 349f1e9b6..2256de362 100644
--- a/sources/elementspanel.cpp
+++ b/sources/elementspanel.cpp
@@ -422,10 +422,20 @@ void ElementsPanel::projectWasOpened(QETProject *project) {
 	@param project Projet a enlever du panel
 */
 void ElementsPanel::projectWasClosed(QETProject *project) {
-	if (QTreeWidgetItem *item_to_remove = itemForProject(project)) {
-		GenericPanel::deleteItem(item_to_remove);
-		projects_to_display_.remove(project);
+		//Stop listening to the project and its sheets: the project still
+		//emits while it is torn down (setModified() ->
+		//projectInformationsChanged()), which put its item back, with items
+		//for sheets about to be freed
+	if (project) {
+		disconnect(project, nullptr, this, nullptr);
+		disconnect(project->embeddedTitleBlockTemplatesCollection(), nullptr, this, nullptr);
 	}
+	if (QTreeWidgetItem *item_to_remove = itemForProject(project)) {
+		for (QTreeWidgetItem *sheet : childItems(item_to_remove, QET::Diagram))
+			disconnect(valueForItem<Diagram *>(sheet), nullptr, this, nullptr);
+		GenericPanel::deleteItem(item_to_remove);
+	}
+	projects_to_display_.remove(project);
 	emit(panelContentChanged());
 }
 
diff --git a/tests/qttest/CMakeLists.txt b/tests/qttest/CMakeLists.txt
index 25dedbbbe..c2566723f 100644
--- a/tests/qttest/CMakeLists.txt
+++ b/tests/qttest/CMakeLists.txt
@@ -1445,3 +1445,7 @@ if(QET_HAS_SCRIPTING)
     "QET_TEST_BINARY_PATH=\"$<TARGET_FILE:qelectrotech>\""
     "QET_EXAMPLES_DIR=\"${QET_DIR}/examples\"")
 endif()
+
+# Closing a modified project with Discard left it in the project tree, with
+# items for its freed sheets; a click on one crashed (forum topic 3215).
+qet_add_app_test(tst_elementspanelclosedproject tst_elementspanelclosedproject.cpp)
diff --git a/tests/qttest/tst_elementspanelclosedproject.cpp b/tests/qttest/tst_elementspanelclosedproject.cpp
new file mode 100644
index 000000000..b31a1697a
--- /dev/null
+++ b/tests/qttest/tst_elementspanelclosedproject.cpp
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include "qetapptest.h"
+
+#include "elementspanel.h"
+#include "elementspanelwidget.h"
+#include "genericpanel.h"
+#include "projectview.h"
+#include "qetproject.h"
+
+#include <QAbstractButton>
+#include <QMessageBox>
+#include <QPointer>
+#include <QTimer>
+
+// Closing a modified project and choosing Discard left the project in the
+// project tree: the project still emitted projectInformationsChanged() while
+// it was torn down, and the panel added it back, with items for its sheets.
+// A click on one of those sheets then crashed in diagram->showMe() on the
+// freed sheet (forum topic 3215, issue #1548).
+class tst_elementspanelclosedproject : public QObject
+{
+	Q_OBJECT
+
+	private slots:
+		void discardedProjectLeavesTheTree()
+		{
+			QETDiagramEditor *editor = QetAppTest::editor();
+			QVERIFY(editor);
+			auto *panel_widget = editor->findChild<ElementsPanelWidget *>();
+			QVERIFY(panel_widget);
+			ElementsPanel &panel = panel_widget->elementsPanel();
+				// What the app does 250 ms after the panel is first shown.
+			panel.reload();
+
+			QVERIFY(editor->newProject());
+			QPointer<QETProject> project = editor->currentProjectView()->project();
+			project->addNewDiagram();
+			QVERIFY(project->projectWasModified());
+			QTreeWidgetItem *project_item = panel.itemForProject(project);
+			QVERIFY(project_item);
+
+				// Answer "Discard" to "Do you want to save changes?".
+			bool answered = false;
+			QTimer answer;
+			connect(&answer, &QTimer::timeout, this, [&answered]() {
+				if (auto *box = qobject_cast<QMessageBox *>(QApplication::activeModalWidget())) {
+					if (QAbstractButton *discard = box->button(QMessageBox::Discard)) {
+						answered = true;
+						discard->click();
+					}
+				}
+			});
+			answer.start(20);
+
+				// Close it from the project tree's context menu.
+			panel.setCurrentItem(project_item);
+			panel_widget->closeProject();
+			answer.stop();
+			QVERIFY(answered);
+			QTRY_VERIFY(project.isNull());
+
+			for (int i = 0; i < panel.topLevelItemCount(); ++i) {
+				QTreeWidgetItem *item = panel.topLevelItem(i);
+				QVERIFY2(item->type() != QET::Project,
+					qPrintable(QStringLiteral("the closed project is still in the tree: %1").arg(item->text(0))));
+			}
+		}
+};
+
+QET_APP_TEST_MAIN(tst_elementspanelclosedproject)
+
+#include "tst_elementspanelclosedproject.moc"