diff --git a/src/sprite.cpp b/src/sprite.cpp
index 49d9f29..9603099 100644
--- a/src/sprite.cpp
+++ b/src/sprite.cpp
@@ -332,7 +332,7 @@ void Sprite::setBitmap(Bitmap *bitmap)
 
 	p->bitmap = bitmap;
 
-	if (!bitmap)
+	if (nullOrDisposed(bitmap))
 		return;
 
 	bitmap->ensureNonMega();
diff --git a/src/window.cpp b/src/window.cpp
index 6b94586..0e78521 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -727,7 +727,7 @@ void Window::setWindowskin(Bitmap *value)
 
 	p->windowskin = value;
 
-	if (!value)
+	if (nullOrDisposed(value))
 		return;
 
 	value->ensureNonMega();
@@ -743,7 +743,7 @@ void Window::setContents(Bitmap *value)
 	p->contents = value;
 	p->controlsVertDirty = true;
 
-	if (!value)
+	if (nullOrDisposed(value))
 		return;
 
 	value->ensureNonMega();
diff --git a/src/windowvx.cpp b/src/windowvx.cpp
index 84f5ab8..9af98ad 100644
--- a/src/windowvx.cpp
+++ b/src/windowvx.cpp
@@ -921,6 +921,9 @@ void WindowVX::setContents(Bitmap *value)
 
 	p->contents = value;
 
+	if (nullOrDisposed(value))
+		return;
+
 	FloatRect rect = p->contents->rect();
 	p->contentsQuad.setTexPosRect(rect, rect);
 	p->ctrlVertDirty = true;