diff --git a/docs/API/GLFW/glfwSetWindowMonitor.md b/docs/API/GLFW/glfwSetWindowMonitor.md
index ccd2cf4f..d8334dd4 100644
--- a/docs/API/GLFW/glfwSetWindowMonitor.md
+++ b/docs/API/GLFW/glfwSetWindowMonitor.md
@@ -2,7 +2,7 @@
 Sets the mode, monitor, video mode and placement of a window.
 
 ```php
-function glfwSetWindowMonitor(\GLFWwindow $window, \GLFWmonitor $monitor, int $xpos, int $ypos, int $width, int $height, int $refreshRate) : void
+function glfwSetWindowMonitor(\GLFWwindow $window, ?\GLFWmonitor $monitor, int $xpos, int $ypos, int $width, int $height, int $refreshRate) : void
 ```
 
 This function sets the monitor that the window uses for full screen mode or,
@@ -28,7 +28,7 @@ arguments
 
 :    1. `\GLFWwindow` `$window` The window whose monitor, size or video mode to
     set.
-    2. `\GLFWmonitor` `$monitor` The desired monitor, or `NULL` to set windowed
+    2. `?\GLFWmonitor` `$monitor` The desired monitor, or `NULL` to set windowed
     mode.
     3. `int` `$xpos` The desired x-coordinate of the upper-left corner of the
     content area.
diff --git a/generator/build b/generator/build
index d756449d..e1d7f70d 100755
--- a/generator/build
+++ b/generator/build
@@ -63,6 +63,7 @@ $gen->adjust(PHPGlfwAdjustments\GLFWSwapBuffersAdjustment::class);
 $gen->adjust(PHPGlfwAdjustments\GLFWCallbacksAdjustment::class);
 $gen->adjust(PHPGlfwAdjustments\GLFWCreateWindowAdjustment::class);
 $gen->adjust(PHPGlfwAdjustments\GLFWGetVideoModesAdjustment::class);
+$gen->adjust(PHPGlfwAdjustments\GLFWSetWindowMonitorAdjustment::class);
 $gen->adjust(PHPGlfwAdjustments\GLShaderSourceAdjustment::class);
 $gen->adjust(PHPGlfwAdjustments\GLBufferDataAdjustment::class);
 $gen->adjust(PHPGlfwAdjustments\GLVertexAttribPointerAdjustment::class);
diff --git a/generator/src/ExtArgument.php b/generator/src/ExtArgument.php
index eff882f7..479bfe9f 100644
--- a/generator/src/ExtArgument.php
+++ b/generator/src/ExtArgument.php
@@ -121,6 +121,11 @@ public static function make(string $name, string $argumentType) : ExtArgument
      */
     public bool $isParsed = true;
 
+    /**
+     * Is the argument nullable? can null be passed instead of the desired type?
+     */
+    public bool $isNullable = false;
+
     /**
      * Constrcutor
      * @param string $name The name of the argument 
diff --git a/generator/src/ExtArgument/InternalPtrObjectArgument.php b/generator/src/ExtArgument/InternalPtrObjectArgument.php
index 6f7c349d..6b1ca55d 100644
--- a/generator/src/ExtArgument/InternalPtrObjectArgument.php
+++ b/generator/src/ExtArgument/InternalPtrObjectArgument.php
@@ -44,7 +44,7 @@ public function typeIsOfSameInternalSize() : bool
     public function getCharId() : string 
     {
         $c = $this->charid;
-        if ($this->isOptional()) $c .= '!';
+        if ($this->isOptional() || $this->isNullable) $c .= '!';
 
         return $c;
     }
@@ -78,7 +78,7 @@ public function getZendParameterParseArguments() : array
      */
     public function getUsePrepCode() : string 
     {
-        return $this->argInternalPtrObject->getInternalPtrFromZValDeclarationCode($this->name, $this->getZValName(), $this->defaultValue);
+        return $this->argInternalPtrObject->getInternalPtrFromZValDeclarationCode($this->name, $this->getZValName(), $this->defaultValue, $this->isNullable);
     }
 
     /**
diff --git a/generator/src/ExtFunction.php b/generator/src/ExtFunction.php
index 52791f04..3464e1a1 100644
--- a/generator/src/ExtFunction.php
+++ b/generator/src/ExtFunction.php
@@ -329,7 +329,7 @@ public function getPHPStubArgument(ExtArgument $arg, bool $allowDefaultValue = t
     {
         // IPO argument
         if ($arg->argumentType === ExtType::T_IPO) {
-            $buffer = ($arg->isOptional() ? '?' : '') . $arg->argInternalPtrObject->getPHPClassName() . ' ' . '$' . $arg->name;
+            $buffer = ($arg->isOptional() || $arg->isNullable ? '?' : '') . $arg->argInternalPtrObject->getPHPClassName() . ' ' . '$' . $arg->name;
                 
             if ($arg->isOptional() && $allowDefaultValue) {
                 $buffer .= ' = ' . $arg->defaultValue;
@@ -339,7 +339,7 @@ public function getPHPStubArgument(ExtArgument $arg, bool $allowDefaultValue = t
         }
         // class entry argument
         elseif ($arg->argumentType === ExtType::T_CE && $arg instanceof CEObjectArgument) {
-            $buffer = ($arg->isOptional() ? '?' : '') . $arg->getPHPClassName() . ' ' . ($arg->explicitPassedByReference ? '&' : '') . '$' . $arg->name;
+            $buffer = ($arg->isOptional() || $arg->isNullable ? '?' : '') . $arg->getPHPClassName() . ' ' . ($arg->explicitPassedByReference ? '&' : '') . '$' . $arg->name;
                 
             if ($arg->isOptional() && $allowDefaultValue) {
                 $buffer .= ' = ' . $arg->defaultValue;
diff --git a/generator/src/ExtInternalPtrObject.php b/generator/src/ExtInternalPtrObject.php
index ac53f361..5162be5f 100644
--- a/generator/src/ExtInternalPtrObject.php
+++ b/generator/src/ExtInternalPtrObject.php
@@ -159,9 +159,9 @@ public function getObjectMinitHelperFunctionName()
     /**
      * Returns C code that declares the given varname of the internal type by resolving a zval potiner
      */
-    public function getInternalPtrFromZValDeclarationCode(string $internalVarName, string $zvalVarName, ?string $defaultValue = null) : string 
+    public function getInternalPtrFromZValDeclarationCode(string $internalVarName, string $zvalVarName, ?string $defaultValue = null, bool $isNullable = false) : string 
     {
-        if ($defaultValue !== null) {
+        if ($defaultValue !== null || $isNullable) {
             $b = $this->type . ' ' . $internalVarName . ' = NULL;' . PHP_EOL;
             $b .= sprintf("if (%s != NULL && Z_TYPE_P(%s) == IS_OBJECT) {\n", $zvalVarName, $zvalVarName);
             $b .= sprintf("    %s = %s(%s);\n}", $internalVarName, $this->getInternalPtrFromZValPtrFunctionName(), $zvalVarName);
diff --git a/generator/src/PHPGlfwAdjustments/GLFWSetWindowMonitorAdjustment.php b/generator/src/PHPGlfwAdjustments/GLFWSetWindowMonitorAdjustment.php
new file mode 100644
index 00000000..561f6f82
--- /dev/null
+++ b/generator/src/PHPGlfwAdjustments/GLFWSetWindowMonitorAdjustment.php
@@ -0,0 +1,22 @@
+<?php 
+
+namespace PHPGlfwAdjustments;
+
+use ExtGenerator;
+
+class GLFWSetWindowMonitorAdjustment implements AdjustmentInterface
+{
+    /**
+     * Recieves an instance of the extension generator before beeing built to 
+     * make changes / adjustments for the extension to handle edge cases whithout 
+     * adding a million ifs into the parser code.
+     */
+    public function handle(ExtGenerator $gen) : void
+    {
+        $setMonitorFunc = $gen->getFunctionByName('glfwSetWindowMonitor');
+
+        // monitor needs to be optional (nullable) if you want to force back 
+        // windowed mode
+        $setMonitorFunc->arguments[1]->isNullable = true;
+    }
+}
\ No newline at end of file
diff --git a/phpglfw.stub.php b/phpglfw.stub.php
index e76c255a..af4e9095 100644
--- a/phpglfw.stub.php
+++ b/phpglfw.stub.php
@@ -2715,7 +2715,7 @@ function glfwHideWindow(GLFWwindow $window) : void {}
     function glfwFocusWindow(GLFWwindow $window) : void {}
     function glfwRequestWindowAttention(GLFWwindow $window) : void {}
     function glfwGetWindowMonitor(GLFWwindow $window) : GLFWmonitor {}
-    function glfwSetWindowMonitor(GLFWwindow $window, GLFWmonitor $monitor, int $xpos, int $ypos, int $width, int $height, int $refreshRate) : void {}
+    function glfwSetWindowMonitor(GLFWwindow $window, ?GLFWmonitor $monitor, int $xpos, int $ypos, int $width, int $height, int $refreshRate) : void {}
     function glfwGetWindowAttrib(GLFWwindow $window, int $attrib) : int {}
     function glfwSetWindowAttrib(GLFWwindow $window, int $attrib, int $value) : void {}
     function glfwSetWindowPosCallback(GLFWwindow $window, callable $callback) : void {}
diff --git a/phpglfw_arginfo.h b/phpglfw_arginfo.h
index e14780df..a4acea80 100644
--- a/phpglfw_arginfo.h
+++ b/phpglfw_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: b0d79ff50f0ceba7e80a0de9e20cc3b5dfd7fa96 */
+ * Stub hash: 5987166c03bdd5557449c93647771b2487551a2c */
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_glCullFace, 0, 1, IS_VOID, 0)
 	ZEND_ARG_TYPE_INFO(0, mode, IS_LONG, 0)
@@ -2051,7 +2051,7 @@ ZEND_END_ARG_INFO()
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_glfwSetWindowMonitor, 0, 7, IS_VOID, 0)
 	ZEND_ARG_OBJ_INFO(0, window, GLFWwindow, 0)
-	ZEND_ARG_OBJ_INFO(0, monitor, GLFWmonitor, 0)
+	ZEND_ARG_OBJ_INFO(0, monitor, GLFWmonitor, 1)
 	ZEND_ARG_TYPE_INFO(0, xpos, IS_LONG, 0)
 	ZEND_ARG_TYPE_INFO(0, ypos, IS_LONG, 0)
 	ZEND_ARG_TYPE_INFO(0, width, IS_LONG, 0)
diff --git a/phpglfw_functions.c b/phpglfw_functions.c
index 4ad5e092..74c084d8 100644
--- a/phpglfw_functions.c
+++ b/phpglfw_functions.c
@@ -11337,11 +11337,14 @@ PHP_FUNCTION(glfwSetWindowMonitor)
     zend_long width;
     zend_long height;
     zend_long refreshRate;
-    if (zend_parse_parameters(ZEND_NUM_ARGS() , "OOlllll", &window_zval, phpglfw_glfwwindow_ce, &monitor_zval, phpglfw_glfwmonitor_ce, &xpos, &ypos, &width, &height, &refreshRate) == FAILURE) {
+    if (zend_parse_parameters(ZEND_NUM_ARGS() , "OO!lllll", &window_zval, phpglfw_glfwwindow_ce, &monitor_zval, phpglfw_glfwmonitor_ce, &xpos, &ypos, &width, &height, &refreshRate) == FAILURE) {
         return;
     }
     GLFWwindow* window = phpglfw_glfwwindowptr_from_zval_ptr(window_zval);
-    GLFWmonitor* monitor = phpglfw_glfwmonitorptr_from_zval_ptr(monitor_zval);
+    GLFWmonitor* monitor = NULL;
+    if (monitor_zval != NULL && Z_TYPE_P(monitor_zval) == IS_OBJECT) {
+        monitor = phpglfw_glfwmonitorptr_from_zval_ptr(monitor_zval);
+    }
     glfwSetWindowMonitor(window, monitor, xpos, ypos, width, height, refreshRate);
 } 
 
diff --git a/stubs/phpglfw.php b/stubs/phpglfw.php
index 784129ce..7b25745c 100644
--- a/stubs/phpglfw.php
+++ b/stubs/phpglfw.php
@@ -9495,7 +9495,7 @@ function glfwGetWindowMonitor(GLFWwindow $window) : GLFWmonitor {}
      * 
      * @param GLFWwindow $window The window whose monitor, size or video mode to
      * set.
-     * @param GLFWmonitor $monitor The desired monitor, or `NULL` to set windowed
+     * @param ?GLFWmonitor $monitor The desired monitor, or `NULL` to set windowed
      * mode.
      * @param int $xpos The desired x-coordinate of the upper-left corner of the
      * content area.
@@ -9510,7 +9510,7 @@ function glfwGetWindowMonitor(GLFWwindow $window) : GLFWmonitor {}
      * 
      * @return void
      */ 
-    function glfwSetWindowMonitor(GLFWwindow $window, GLFWmonitor $monitor, int $xpos, int $ypos, int $width, int $height, int $refreshRate) : void {}
+    function glfwSetWindowMonitor(GLFWwindow $window, ?GLFWmonitor $monitor, int $xpos, int $ypos, int $width, int $height, int $refreshRate) : void {}
  
     /**
      * Returns an attribute of the specified window.