diff --git a/modules/juce_audio_devices/audio_io/juce_AudioDeviceManager.cpp b/modules/juce_audio_devices/audio_io/juce_AudioDeviceManager.cpp
index 144edd5997..9d2041d2b2 100644
--- a/modules/juce_audio_devices/audio_io/juce_AudioDeviceManager.cpp
+++ b/modules/juce_audio_devices/audio_io/juce_AudioDeviceManager.cpp
@@ -886,8 +886,7 @@ void AudioDeviceManager::setDefaultMidiOutput (const String& deviceName)
 
         {
             const ScopedLock sl (audioCallbackLock);
-            oldCallbacks = callbacks;
-            callbacks.clear();
+            oldCallbacks.swapWith (callbacks);
         }
 
         if (currentAudioDevice != nullptr)
@@ -906,7 +905,7 @@ void AudioDeviceManager::setDefaultMidiOutput (const String& deviceName)
 
         {
             const ScopedLock sl (audioCallbackLock);
-            callbacks = oldCallbacks;
+            oldCallbacks.swapWith (callbacks);
         }
 
         updateXml();
diff --git a/modules/juce_graphics/geometry/juce_Rectangle.h b/modules/juce_graphics/geometry/juce_Rectangle.h
index 5903d9f024..280cc28f74 100644
--- a/modules/juce_graphics/geometry/juce_Rectangle.h
+++ b/modules/juce_graphics/geometry/juce_Rectangle.h
@@ -290,7 +290,11 @@ public:
         return *this;
     }
 
-    /** Scales this rectangle by the given amount, centred around the origin. */
+    /** Returns a rectangle that has been scaled by the given amount, centred around the origin.
+        Note that if the rectangle has int coordinates and it's scaled by a
+        floating-point amount, then the result will be converted back to integer
+        coordinates using getSmallestIntegerContainer().
+    */
     template <typename FloatType>
     Rectangle operator* (FloatType scaleFactor) const noexcept
     {
@@ -299,7 +303,11 @@ public:
         return r;
     }
 
-    /** Scales this rectangle by the given amount, centred around the origin. */
+    /** Scales this rectangle by the given amount, centred around the origin.
+        Note that if the rectangle has int coordinates and it's scaled by a
+        floating-point amount, then the result will be converted back to integer
+        coordinates using getSmallestIntegerContainer().
+    */
     template <typename FloatType>
     Rectangle operator*= (FloatType scaleFactor) noexcept
     {