Window Assertion Failed on close

[labordep]

When my window are closing I get an Assertion Failed with Pharo Console warnings.

Message (from SDL I suppose) :

Pharo console on bottom :

Code :

| loginWindow loginView container |
loginWindow := PenWindow new.
loginWindow title: 'Test Window'.
loginWindow size: 800@200.
loginWindow position: 50@50.
loginWindow resizable: false.
	
loginView := PenView new key: #loginView.
container := PenContainer new.	
loginView displayComponent: container.
	
loginWindow addDock: (PenViewDock with: loginView).
loginWindow open.

Infos :
Pharo 8.0.0
Build information: Pharo-8.0.0+build.1106.sha.763a1788342108e4cbc14b8092594123f936890f (64 Bit)

Thanks.
Pierre