diff --git a/src/servers/app/DefaultDecorator.cpp b/src/servers/app/DefaultDecorator.cpp
index 9c0d066bbe..341b66fd4c 100644
--- a/src/servers/app/DefaultDecorator.cpp
+++ b/src/servers/app/DefaultDecorator.cpp
@@ -136,6 +136,23 @@ DefaultDecorator::SetLook(DesktopSettings& settings,
 void
 DefaultDecorator::SetFlags(uint32 flags, BRegion* updateRegion)
 {
+	// TODO: we could be much smarter about the update region
+
+	// get previous extent
+	if (updateRegion != NULL) {
+		BRegion extent;
+		GetFootprint(&extent);
+		updateRegion->Include(&extent);
+	}
+
+	Decorator::SetFlags(flags, updateRegion);
+	_DoLayout();
+
+	if (updateRegion != NULL) {
+		BRegion extent;
+		GetFootprint(&extent);
+		updateRegion->Include(&extent);
+	}
 }
 
 
diff --git a/src/servers/app/WindowLayer.cpp b/src/servers/app/WindowLayer.cpp
index 34e3b28811..cd0ca255c5 100644
--- a/src/servers/app/WindowLayer.cpp
+++ b/src/servers/app/WindowLayer.cpp
@@ -725,7 +725,16 @@ WindowLayer::SetFeel(window_feel feel)
 void
 WindowLayer::SetWindowFlags(uint32 flags, BRegion* updateRegion)
 {
-	// TODO: implement settings window flags
+	fWindowFlags = flags;
+
+	if (fDecorator == NULL)
+		return;
+
+	fDecorator->SetFlags(flags, updateRegion);
+	fRebuildDecRegion = true;
+
+	// TODO: we might need to resize the window!
+	//fDecorator->GetSizeLimits(&fMinWidth, &fMinHeight, &fMaxWidth, &fMaxHeight);
 }