diff --git a/src/window.cpp b/src/window.cpp
index 12a401a963..8bb436ad7b 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -2125,7 +2125,7 @@ static EventState HandleWindowDragging()
 				break;
 			}
 
-			if (w->flags.Test(WindowFlag::CMDragDirtied)) {
+			if (!w->flags.Test(WindowFlag::CMDragDirtied)) {
 				w->flags.Set(WindowFlag::CMDragDirtied);
 				w->SetDirtyAsBlocks();
 			}