diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 5ef5522f..024f1fbd 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -2860,11 +2860,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Spreadsheet.php
 
-		-
-			message: "#^Comparison operation \"\\<\\=\" between int\\<min, \\-1\\> and 1000 is always true\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Spreadsheet.php
-
 		-
 			message: "#^Parameter \\#1 \\$worksheet of method PhpOffice\\\\PhpSpreadsheet\\\\Spreadsheet\\:\\:getIndex\\(\\) expects PhpOffice\\\\PhpSpreadsheet\\\\Worksheet\\\\Worksheet, PhpOffice\\\\PhpSpreadsheet\\\\Worksheet\\\\Worksheet\\|null given\\.$#"
 			count: 1
@@ -2875,21 +2870,11 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Spreadsheet.php
 
-		-
-			message: "#^Result of \\|\\| is always true\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Spreadsheet.php
-
 		-
 			message: "#^Strict comparison using \\=\\=\\= between PhpOffice\\\\PhpSpreadsheet\\\\Spreadsheet and null will always evaluate to false\\.$#"
 			count: 1
 			path: src/PhpSpreadsheet/Spreadsheet.php
 
-		-
-			message: "#^Strict comparison using \\=\\=\\= between string and null will always evaluate to false\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Spreadsheet.php
-
 		-
 			message: "#^Unreachable statement \\- code above always terminates\\.$#"
 			count: 1
diff --git a/src/PhpSpreadsheet/Spreadsheet.php b/src/PhpSpreadsheet/Spreadsheet.php
index 33b4fe0c..4bb93987 100644
--- a/src/PhpSpreadsheet/Spreadsheet.php
+++ b/src/PhpSpreadsheet/Spreadsheet.php
@@ -3,10 +3,13 @@
 namespace PhpOffice\PhpSpreadsheet;
 
 use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx as XlsxReader;
+use PhpOffice\PhpSpreadsheet\Shared\File;
 use PhpOffice\PhpSpreadsheet\Shared\StringHelper;
 use PhpOffice\PhpSpreadsheet\Style\Style;
 use PhpOffice\PhpSpreadsheet\Worksheet\Iterator;
 use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
+use PhpOffice\PhpSpreadsheet\Writer\Xlsx as XlsxWriter;
 
 class Spreadsheet
 {
@@ -1120,28 +1123,24 @@ class Spreadsheet
      */
     public function copy()
     {
-        $copied = clone $this;
+        $filename = File::temporaryFilename();
+        $writer = new XlsxWriter($this);
+        $writer->setIncludeCharts(true);
+        $writer->save($filename);
 
-        $worksheetCount = count($this->workSheetCollection);
-        for ($i = 0; $i < $worksheetCount; ++$i) {
-            $this->workSheetCollection[$i] = $this->workSheetCollection[$i]->copy();
-            $this->workSheetCollection[$i]->rebindParent($this);
-        }
+        $reader = new XlsxReader();
+        $reader->setIncludeCharts(true);
+        $reloadedSpreadsheet = $reader->load($filename);
+        unlink($filename);
 
-        return $copied;
+        return $reloadedSpreadsheet;
     }
 
-    /**
-     * Implement PHP __clone to create a deep clone, not just a shallow copy.
-     */
     public function __clone()
     {
-        // @phpstan-ignore-next-line
-        foreach ($this as $key => $val) {
-            if (is_object($val) || (is_array($val))) {
-                $this->{$key} = unserialize(serialize($val));
-            }
-        }
+        throw new Exception(
+            'Do not use clone on spreadsheet. Use spreadsheet->copy() instead.'
+        );
     }
 
     /**
@@ -1562,7 +1561,7 @@ class Spreadsheet
      *       Workbook window is hidden and cannot be shown in the
      *       user interface.
      *
-     * @param string $visibility visibility status of the workbook
+     * @param null|string $visibility visibility status of the workbook
      */
     public function setVisibility($visibility): void
     {
@@ -1596,7 +1595,7 @@ class Spreadsheet
      */
     public function setTabRatio($tabRatio): void
     {
-        if ($tabRatio >= 0 || $tabRatio <= 1000) {
+        if ($tabRatio >= 0 && $tabRatio <= 1000) {
             $this->tabRatio = (int) $tabRatio;
         } else {
             throw new Exception('Tab ratio must be between 0 and 1000.');
diff --git a/tests/PhpSpreadsheetTests/DefinedNameTest.php b/tests/PhpSpreadsheetTests/DefinedNameTest.php
index 43eddc8a..82950880 100644
--- a/tests/PhpSpreadsheetTests/DefinedNameTest.php
+++ b/tests/PhpSpreadsheetTests/DefinedNameTest.php
@@ -85,6 +85,18 @@ class DefinedNameTest extends TestCase
         self::assertCount(1, $this->spreadsheet->getDefinedNames());
     }
 
+    public function testRemoveGlobalDefinedName(): void
+    {
+        $this->spreadsheet->addDefinedName(
+            DefinedName::createInstance('Any', $this->spreadsheet->getActiveSheet(), '=A1')
+        );
+        self::assertCount(1, $this->spreadsheet->getDefinedNames());
+
+        $this->spreadsheet->removeDefinedName('Any');
+        self::assertCount(0, $this->spreadsheet->getDefinedNames());
+        $this->spreadsheet->removeDefinedName('Other');
+    }
+
     public function testRemoveGlobalDefinedNameWhenDuplicateNames(): void
     {
         $this->spreadsheet->addDefinedName(
diff --git a/tests/PhpSpreadsheetTests/NamedFormulaTest.php b/tests/PhpSpreadsheetTests/NamedFormulaTest.php
index 4c4a6b11..02e9d818 100644
--- a/tests/PhpSpreadsheetTests/NamedFormulaTest.php
+++ b/tests/PhpSpreadsheetTests/NamedFormulaTest.php
@@ -133,4 +133,10 @@ class NamedFormulaTest extends TestCase
             $formula->getValue()
         );
     }
+
+    public function testRemoveNonExistentNamedFormula(): void
+    {
+        self::assertCount(0, $this->spreadsheet->getNamedFormulae());
+        $this->spreadsheet->removeNamedFormula('Any');
+    }
 }
diff --git a/tests/PhpSpreadsheetTests/NamedRangeTest.php b/tests/PhpSpreadsheetTests/NamedRangeTest.php
index c72b7b73..402e7eba 100644
--- a/tests/PhpSpreadsheetTests/NamedRangeTest.php
+++ b/tests/PhpSpreadsheetTests/NamedRangeTest.php
@@ -133,4 +133,10 @@ class NamedRangeTest extends TestCase
             $range->getValue()
         );
     }
+
+    public function testRemoveNonExistentNamedRange(): void
+    {
+        self::assertCount(0, $this->spreadsheet->getNamedRanges());
+        $this->spreadsheet->removeNamedRange('Any');
+    }
 }
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/RibbonTest.php b/tests/PhpSpreadsheetTests/Reader/Xlsx/RibbonTest.php
index 197ad47f..ab304e7b 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xlsx/RibbonTest.php
+++ b/tests/PhpSpreadsheetTests/Reader/Xlsx/RibbonTest.php
@@ -44,4 +44,34 @@ class RibbonTest extends AbstractFunctional
         self::assertNull($reloadedSpreadsheet->getRibbonBinObjects());
         $reloadedSpreadsheet->disconnectWorksheets();
     }
+
+    /**
+     * Same as above but discard macros.
+     */
+    public function testDiscardMacros(): void
+    {
+        $filename = 'tests/data/Reader/XLSX/ribbon.donotopen.zip';
+        $reader = IOFactory::createReader('Xlsx');
+        $spreadsheet = $reader->load($filename);
+        self::assertTrue($spreadsheet->hasRibbon());
+        $target = $spreadsheet->getRibbonXMLData('target');
+        self::assertSame('customUI/customUI.xml', $target);
+        $data = $spreadsheet->getRibbonXMLData('data');
+        self::assertIsString($data);
+        self::assertSame(1522, strlen($data));
+        $vbaCode = (string) $spreadsheet->getMacrosCode();
+        self::assertSame(13312, strlen($vbaCode));
+        $spreadsheet->discardMacros();
+
+        $reloadedSpreadsheet = $this->writeAndReload($spreadsheet, 'Xlsx');
+        $spreadsheet->disconnectWorksheets();
+        self::assertTrue($reloadedSpreadsheet->hasRibbon());
+        $ribbonData = $reloadedSpreadsheet->getRibbonXmlData();
+        self::assertIsArray($ribbonData);
+        self::assertSame($target, $ribbonData['target'] ?? '');
+        self::assertSame($data, $ribbonData['data'] ?? '');
+        self::assertNull($reloadedSpreadsheet->getMacrosCode());
+        self::assertNull($reloadedSpreadsheet->getRibbonBinObjects());
+        $reloadedSpreadsheet->disconnectWorksheets();
+    }
 }
diff --git a/tests/PhpSpreadsheetTests/SpreadsheetCoverageTest.php b/tests/PhpSpreadsheetTests/SpreadsheetCoverageTest.php
new file mode 100644
index 00000000..584c53fe
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/SpreadsheetCoverageTest.php
@@ -0,0 +1,209 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests;
+
+use PhpOffice\PhpSpreadsheet\Exception as SSException;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Style\Style;
+use PHPUnit\Framework\TestCase;
+
+class SpreadsheetCoverageTest extends TestCase
+{
+    public function testDocumentProperties(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $properties = $spreadsheet->getProperties();
+        $properties->setCreator('Anyone');
+        $properties->setTitle('Description');
+        $spreadsheet2 = new Spreadsheet();
+        self::assertNotEquals($properties, $spreadsheet2->getProperties());
+        $properties2 = clone $properties;
+        $spreadsheet2->setProperties($properties2);
+        self::assertEquals($properties, $spreadsheet2->getProperties());
+        $spreadsheet->disconnectWorksheets();
+        $spreadsheet2->disconnectWorksheets();
+    }
+
+    public function testDocumentSecurity(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $security = $spreadsheet->getSecurity();
+        $security->setLockRevision(true);
+        $revisionsPassword = 'revpasswd';
+        $security->setRevisionsPassword($revisionsPassword);
+        $spreadsheet2 = new Spreadsheet();
+        self::assertNotEquals($security, $spreadsheet2->getSecurity());
+        $security2 = clone $security;
+        $spreadsheet2->setSecurity($security2);
+        self::assertEquals($security, $spreadsheet2->getSecurity());
+        $spreadsheet->disconnectWorksheets();
+        $spreadsheet2->disconnectWorksheets();
+    }
+
+    public function testCellXfCollection(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->getStyle('A1')->getFont()->setName('font1');
+        $sheet->getStyle('A2')->getFont()->setName('font2');
+        $sheet->getStyle('A3')->getFont()->setName('font3');
+        $sheet->getStyle('B1')->getFont()->setName('font1');
+        $sheet->getStyle('B2')->getFont()->setName('font2');
+        $collection = $spreadsheet->getCellXfCollection();
+        self::assertCount(4, $collection);
+        $font1Style = $collection[1];
+        self::assertTrue($spreadsheet->cellXfExists($font1Style));
+        self::assertSame('font1', $spreadsheet->getCellXfCollection()[1]->getFont()->getName());
+        self::assertSame('font1', $sheet->getStyle('A1')->getFont()->getName());
+        self::assertSame('font2', $sheet->getStyle('A2')->getFont()->getName());
+        self::assertSame('font3', $sheet->getStyle('A3')->getFont()->getName());
+        self::assertSame('font1', $sheet->getStyle('B1')->getFont()->getName());
+        self::assertSame('font2', $sheet->getStyle('B2')->getFont()->getName());
+
+        $spreadsheet->removeCellXfByIndex(1);
+        self::assertFalse($spreadsheet->cellXfExists($font1Style));
+        self::assertSame('font2', $spreadsheet->getCellXfCollection()[1]->getFont()->getName());
+        self::assertSame('Calibri', $sheet->getStyle('A1')->getFont()->getName());
+        self::assertSame('font2', $sheet->getStyle('A2')->getFont()->getName());
+        self::assertSame('font3', $sheet->getStyle('A3')->getFont()->getName());
+        self::assertSame('Calibri', $sheet->getStyle('B1')->getFont()->getName());
+        self::assertSame('font2', $sheet->getStyle('B2')->getFont()->getName());
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public function testInvalidRemoveCellXfByIndex(): void
+    {
+        $this->expectException(SSException::class);
+        $this->expectExceptionMessage('CellXf index is out of bounds.');
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->getStyle('A1')->getFont()->setName('font1');
+        $sheet->getStyle('A2')->getFont()->setName('font2');
+        $sheet->getStyle('A3')->getFont()->setName('font3');
+        $sheet->getStyle('B1')->getFont()->setName('font1');
+        $sheet->getStyle('B2')->getFont()->setName('font2');
+        $spreadsheet->removeCellXfByIndex(5);
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public function testInvalidRemoveDefaultStyle(): void
+    {
+        $this->expectException(SSException::class);
+        $this->expectExceptionMessage('No default style found for this workbook');
+        // Removing default style probably should be disallowed.
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $spreadsheet->removeCellXfByIndex(0);
+        $style = $spreadsheet->getDefaultStyle();
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public function testCellStyleXF(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $collection = $spreadsheet->getCellStyleXfCollection();
+        self::assertCount(1, $collection);
+        $styleXf = $collection[0];
+        self::assertSame($styleXf, $spreadsheet->getCellStyleXfByIndex(0));
+        $hash = $styleXf->getHashCode();
+        self::assertSame($styleXf, $spreadsheet->getCellStyleXfByHashCode($hash));
+        self::assertFalse($spreadsheet->getCellStyleXfByHashCode($hash . 'x'));
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public function testInvalidRemoveCellStyleXfByIndex(): void
+    {
+        $this->expectException(SSException::class);
+        $this->expectExceptionMessage('CellStyleXf index is out of bounds.');
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $spreadsheet->removeCellStyleXfByIndex(5);
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public function testInvalidFirstSheetIndex(): void
+    {
+        $this->expectException(SSException::class);
+        $this->expectExceptionMessage('First sheet index must be a positive integer.');
+        $spreadsheet = new Spreadsheet();
+        $spreadsheet->setFirstSheetIndex(-1);
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public function testInvalidVisibility(): void
+    {
+        $this->expectException(SSException::class);
+        $this->expectExceptionMessage('Invalid visibility value.');
+        $spreadsheet = new Spreadsheet();
+        $spreadsheet->setVisibility(Spreadsheet::VISIBILITY_HIDDEN);
+        self::assertSame(Spreadsheet::VISIBILITY_HIDDEN, $spreadsheet->getVisibility());
+        $spreadsheet->setVisibility(null);
+        self::assertSame(Spreadsheet::VISIBILITY_VISIBLE, $spreadsheet->getVisibility());
+        $spreadsheet->setVisibility('badvalue');
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public function testInvalidTabRatio(): void
+    {
+        $this->expectException(SSException::class);
+        $this->expectExceptionMessage('Tab ratio must be between 0 and 1000.');
+        $spreadsheet = new Spreadsheet();
+        $spreadsheet->setTabRatio(2000);
+        $spreadsheet->disconnectWorksheets();
+    }
+
+    public function testCopy(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->getStyle('A1')->getFont()->setName('font1');
+        $sheet->getStyle('A2')->getFont()->setName('font2');
+        $sheet->getStyle('A3')->getFont()->setName('font3');
+        $sheet->getStyle('B1')->getFont()->setName('font1');
+        $sheet->getStyle('B2')->getFont()->setName('font2');
+        $sheet->getCell('A1')->setValue('this is a1');
+        $sheet->getCell('A2')->setValue('this is a2');
+        $sheet->getCell('A3')->setValue('this is a3');
+        $sheet->getCell('B1')->setValue('this is b1');
+        $sheet->getCell('B2')->setValue('this is b2');
+        $copied = $spreadsheet->copy();
+        $copysheet = $copied->getActiveSheet();
+        $copysheet->getStyle('A2')->getFont()->setName('font12');
+        $copysheet->getCell('A2')->setValue('this was a2');
+
+        self::assertSame('font1', $sheet->getStyle('A1')->getFont()->getName());
+        self::assertSame('font2', $sheet->getStyle('A2')->getFont()->getName());
+        self::assertSame('font3', $sheet->getStyle('A3')->getFont()->getName());
+        self::assertSame('font1', $sheet->getStyle('B1')->getFont()->getName());
+        self::assertSame('font2', $sheet->getStyle('B2')->getFont()->getName());
+        self::assertSame('this is a1', $sheet->getCell('A1')->getValue());
+        self::assertSame('this is a2', $sheet->getCell('A2')->getValue());
+        self::assertSame('this is a3', $sheet->getCell('A3')->getValue());
+        self::assertSame('this is b1', $sheet->getCell('B1')->getValue());
+        self::assertSame('this is b2', $sheet->getCell('B2')->getValue());
+
+        self::assertSame('font1', $copysheet->getStyle('A1')->getFont()->getName());
+        self::assertSame('font12', $copysheet->getStyle('A2')->getFont()->getName());
+        self::assertSame('font3', $copysheet->getStyle('A3')->getFont()->getName());
+        self::assertSame('font1', $copysheet->getStyle('B1')->getFont()->getName());
+        self::assertSame('font2', $copysheet->getStyle('B2')->getFont()->getName());
+        self::assertSame('this is a1', $copysheet->getCell('A1')->getValue());
+        self::assertSame('this was a2', $copysheet->getCell('A2')->getValue());
+        self::assertSame('this is a3', $copysheet->getCell('A3')->getValue());
+        self::assertSame('this is b1', $copysheet->getCell('B1')->getValue());
+        self::assertSame('this is b2', $copysheet->getCell('B2')->getValue());
+
+        $spreadsheet->disconnectWorksheets();
+        $copied->disconnectWorksheets();
+    }
+
+    public function testClone(): void
+    {
+        $this->expectException(SSException::class);
+        $this->expectExceptionMessage('Do not use clone on spreadsheet. Use spreadsheet->copy() instead.');
+        $spreadsheet = new Spreadsheet();
+        $clone = clone $spreadsheet;
+        $spreadsheet->disconnectWorksheets();
+        $clone->disconnectWorksheets();
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Style/FontTest.php b/tests/PhpSpreadsheetTests/Style/FontTest.php
index 02814afa..6cd4d950 100644
--- a/tests/PhpSpreadsheetTests/Style/FontTest.php
+++ b/tests/PhpSpreadsheetTests/Style/FontTest.php
@@ -3,6 +3,7 @@
 namespace PhpOffice\PhpSpreadsheetTests\Style;
 
 use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Style\Font;
 use PHPUnit\Framework\TestCase;
 
 class FontTest extends TestCase
@@ -88,4 +89,20 @@ class FontTest extends TestCase
         self::assertEquals('Calibri', $font->getName(), 'Null string changed to default');
         $spreadsheet->disconnectWorksheets();
     }
+
+    public function testUnderlineHash(): void
+    {
+        $font1 = new Font();
+        $font2 = new Font();
+        $font2aHash = $font2->getHashCode();
+        self::assertSame($font1->getHashCode(), $font2aHash);
+        $font2->setUnderlineColor(
+            [
+                'type' => 'srgbClr',
+                'value' => 'FF0000',
+            ]
+        );
+        $font2bHash = $font2->getHashCode();
+        self::assertNotEquals($font1->getHashCode(), $font2bHash);
+    }
 }