looks like command buffers need to be externally synchronized

src/Engine/UI/Elements/Element.cpp

@@ -1,4 +1,5 @@
 #include "Element.h"
+#include "UI/System.h"
 
 using namespace Seele;
 using namespace Seele::UI;

src/Engine/UI/System.cpp

@@ -1,4 +1,5 @@
 #include "System.h"
+#include "Elements/Panel.h"
 
 using namespace Seele;
 using namespace Seele::UI;