diff --git a/src/kits/app/Looper.cpp b/src/kits/app/Looper.cpp
index b69e0a7746..8121a02b95 100644
--- a/src/kits/app/Looper.cpp
+++ b/src/kits/app/Looper.cpp
@@ -1250,6 +1250,10 @@ BLooper::task_looper()
 					gDefaultTokens.GetToken(messagePrivate.GetTarget(),
 						B_HANDLER_TOKEN, (void **)&handler);
 
+					// if this handler doesn't belong to us, we drop the message
+					if (handler != NULL && handler->Looper() != this)
+						handler = NULL;
+
 					PRINT(("LOOPER: use %ld, handler: %p, this: %p\n",
 						messagePrivate.GetTarget(), handler, this));
 				}
@@ -1271,6 +1275,11 @@ BLooper::task_looper()
 				}
 			}
 
+			if (fTerminating) {
+				// we leave the looper locked when we quit
+				return;
+			}
+
 			// Unlock the looper
 			Unlock();
 
diff --git a/src/kits/interface/Window.cpp b/src/kits/interface/Window.cpp
index 6c47db0abc..85128b6893 100644
--- a/src/kits/interface/Window.cpp
+++ b/src/kits/interface/Window.cpp
@@ -2248,6 +2248,10 @@ BWindow::task_looper()
 				} else {
 					gDefaultTokens.GetToken(messagePrivate.GetTarget(),
 						B_HANDLER_TOKEN, (void **)&handler);
+
+					// if this handler doesn't belong to us, we drop the message
+					if (handler != NULL && handler->Looper() != this)
+						handler = NULL;
 				}
 
 				if (handler == NULL || usePreferred)
@@ -2280,6 +2284,11 @@ BWindow::task_looper()
 				}
 			}
 
+			if (fTerminating) {
+				// we leave the looper locked when we quit
+				return;
+			}
+
 			Unlock();
 
 			// Are any messages on the port?