Square of information over a button is empty

[RemiDufloer]

To Reproduce
Steps to reproduce the behavior:

Downloaded with:

Metacello new
        repository: 'github://pharo-spec/Spec-Gtk';
        baseline: 'SpecGtk';
        onConflict: [ :e | e useIncoming ];
        onUpgrade: [ :e | e useIncoming ];
        ignoreImage;
        load 

Open a calypso on a separate window doing:

presenter := SpPresenter new.
presenter application: (SpApplication new useBackend: #Gtk).
presenter layout: (SpBoxLayout newVertical 
    add: (morph := presenter newMorph);
    yourself).

morph morph: (ClyFullBrowserMorph onDefaultEnvironment).

presenter open.

With you mouse go over a button.

Expected behavior

normally this square is for the user. This block contain a information about the button

Screenshots

Version information:

• Pharo Version [e.g 10]