diff --git a/jre_lwjgl3glfw/src/main/java/org/lwjgl/glfw/GLFW.java b/jre_lwjgl3glfw/src/main/java/org/lwjgl/glfw/GLFW.java
index 41f537102..34594e6b6 100644
--- a/jre_lwjgl3glfw/src/main/java/org/lwjgl/glfw/GLFW.java
+++ b/jre_lwjgl3glfw/src/main/java/org/lwjgl/glfw/GLFW.java
@@ -656,19 +656,35 @@ public class GLFW
 
 // Generated stub callback methods
     public static GLFWCharCallback glfwSetCharCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWcharfun") GLFWCharCallbackI cbfun) {
-        return mGLFWCharCallback = GLFWCharCallback.createSafe(nglfwSetCharCallback(window, memAddressSafe(cbfun)));
+        GLFWCharCallback lastCallback = mGLFWCharCallback;
+        if (cbfun == null) mGLFWCharCallback = null;
+        else mGLFWCharCallback = GLFWCharCallback.createSafe(nglfwSetCharCallback(window, memAddressSafe(cbfun)));
+
+        return lastCallback;
     }
 
     public static GLFWCharModsCallback glfwSetCharModsCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWcharmodsfun") GLFWCharModsCallbackI cbfun) {
-        return mGLFWCharModsCallback = GLFWCharModsCallback.createSafe(nglfwSetCharModsCallback(window, memAddressSafe(cbfun)));
+        GLFWCharModsCallback lastCallback = mGLFWCharModsCallback;
+        if (cbfun == null) mGLFWCharModsCallback = null;
+        else mGLFWCharModsCallback = GLFWCharModsCallback.createSafe(nglfwSetCharModsCallback(window, memAddressSafe(cbfun)));
+
+        return lastCallback;
     }
 
     public static GLFWCursorEnterCallback glfwSetCursorEnterCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWcursorenterfun") GLFWCursorEnterCallbackI cbfun) {
-        return mGLFWCursorEnterCallback = GLFWCursorEnterCallback.createSafe(nglfwSetCursorEnterCallback(window, memAddressSafe(cbfun)));
+        GLFWCursorEnterCallback lastCallback = mGLFWCursorEnterCallback;
+        if (cbfun == null) mGLFWCursorEnterCallback = null;
+        else mGLFWCursorEnterCallback = GLFWCursorEnterCallback.createSafe(nglfwSetCursorEnterCallback(window, memAddressSafe(cbfun)));
+
+        return lastCallback;
     }
 
     public static GLFWCursorPosCallback glfwSetCursorPosCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWcursorposfun") GLFWCursorPosCallbackI cbfun) {
-        return mGLFWCursorPosCallback = GLFWCursorPosCallback.createSafe(nglfwSetCursorPosCallback(window, memAddressSafe(cbfun)));
+        GLFWCursorPosCallback lastCallback = mGLFWCursorPosCallback;
+        if (cbfun == null) mGLFWCursorPosCallback = null;
+        else mGLFWCursorPosCallback = GLFWCursorPosCallback.createSafe(nglfwSetCursorPosCallback(window, memAddressSafe(cbfun)));
+
+        return lastCallback;
     }
     
     public static GLFWDropCallback glfwSetDropCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWdropfun") GLFWDropCallbackI cbfun) {
@@ -688,11 +704,17 @@ public class GLFW
     }
 
     public static GLFWFramebufferSizeCallback glfwSetFramebufferSizeCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWframebuffersizefun") GLFWFramebufferSizeCallbackI cbfun) {
+        GLFWFramebufferSizeCallback lastCallback = mGLFWFramebufferSizeCallback;
+        if (cbfun == null) mGLFWFramebufferSizeCallback = null;
+        else mGLFWFramebufferSizeCallback = GLFWFramebufferSizeCallback.createSafe(nglfwSetFramebufferSizeCallback(window, memAddressSafe(cbfun)));
+
         mGLFWFramebufferSizeCallback = GLFWFramebufferSizeCallback.createSafe(nglfwSetFramebufferSizeCallback(window, memAddressSafe(cbfun)));
+
         try {
             mGLFWFramebufferSizeCallback.invoke(window, mGLFWWindowWidth, mGLFWWindowHeight);
         } catch (Throwable th) {}
-        return mGLFWFramebufferSizeCallback;
+
+        return lastCallback;
     }
 
     public static GLFWJoystickCallback glfwSetJoystickCallback(/* @NativeType("GLFWwindow *") long window, */ @Nullable @NativeType("GLFWjoystickfun") GLFWJoystickCallbackI cbfun) {
@@ -704,7 +726,11 @@ public class GLFW
     }
 
     public static GLFWKeyCallback glfwSetKeyCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWkeyfun") GLFWKeyCallbackI cbfun) {
-        return mGLFWKeyCallback = GLFWKeyCallback.createSafe(nglfwSetKeyCallback(window, memAddressSafe(cbfun)));
+        GLFWKeyCallback lastCallback = mGLFWKeyCallback;
+        if (cbfun == null) mGLFWKeyCallback = null;
+        else mGLFWKeyCallback = GLFWKeyCallback.createSafe(nglfwSetKeyCallback(window, memAddressSafe(cbfun)));
+
+        return lastCallback;
     }
 
     public static GLFWMonitorCallback glfwSetMonitorCallback(@Nullable @NativeType("GLFWmonitorfun") GLFWMonitorCallbackI cbfun) {
@@ -716,11 +742,19 @@ public class GLFW
     }
 
     public static GLFWMouseButtonCallback glfwSetMouseButtonCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWmousebuttonfun") GLFWMouseButtonCallbackI cbfun) {
-        return mGLFWMouseButtonCallback = GLFWMouseButtonCallback.createSafe(nglfwSetMouseButtonCallback(window, memAddressSafe(cbfun)));
+        GLFWMouseButtonCallback lastCallback = mGLFWMouseButtonCallback;
+        if (cbfun == null) mGLFWMouseButtonCallback = null;
+        else mGLFWMouseButtonCallback = GLFWMouseButtonCallback.createSafe(nglfwSetMouseButtonCallback(window, memAddressSafe(cbfun)));
+
+        return lastCallback;
     }
 
     public static GLFWScrollCallback glfwSetScrollCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWscrollfun") GLFWScrollCallbackI cbfun) {
-        return mGLFWScrollCallback = GLFWScrollCallback.createSafe(nglfwSetScrollCallback(window, memAddressSafe(cbfun)));
+        GLFWScrollCallback lastCallback = mGLFWScrollCallback;
+        if (cbfun == null) mGLFWScrollCallback = null;
+        else mGLFWScrollCallback = GLFWScrollCallback.createSafe(nglfwSetScrollCallback(window, memAddressSafe(cbfun)));
+
+        return lastCallback;
     }
 
     public static GLFWWindowCloseCallback glfwSetWindowCloseCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWwindowclosefun") GLFWWindowCloseCallbackI cbfun) {
@@ -779,11 +813,17 @@ public class GLFW
     }
 
     public static GLFWWindowSizeCallback glfwSetWindowSizeCallback(@NativeType("GLFWwindow *") long window, @Nullable @NativeType("GLFWwindowsizefun") GLFWWindowSizeCallbackI cbfun) {
+        GLFWWindowSizeCallback lastCallback = mGLFWWindowSizeCallback;
+        if (cbfun == null) mGLFWWindowSizeCallback = null;
+        else mGLFWWindowSizeCallback = GLFWWindowSizeCallback.createSafe(nglfwSetWindowSizeCallback(window, memAddressSafe(cbfun)));
+
         mGLFWWindowSizeCallback = GLFWWindowSizeCallback.createSafe(nglfwSetWindowSizeCallback(window, memAddressSafe(cbfun)));
+
         try {
             mGLFWWindowSizeCallback.invoke(window, mGLFWWindowWidth, mGLFWWindowHeight);
         } catch (Throwable th) {}
-        return mGLFWWindowSizeCallback;
+
+        return lastCallback;
     }
 
     static boolean isGLFWReady;