diff --git a/Kernel/ProcessGUI.cpp b/Kernel/ProcessGUI.cpp
index 4f849e4e85..f4ba4748d8 100644
--- a/Kernel/ProcessGUI.cpp
+++ b/Kernel/ProcessGUI.cpp
@@ -113,6 +113,7 @@ int Process::gui$invalidate_window(int window_id)
     auto& window = *(*it).value;
     // FIXME: This should queue up a message that the window server process can read.
     //        Poking into its data structures is not good.
+    InterruptDisabler disabler;
     WindowManager::the().invalidate(window);
     return 0;
 }