Package, Class, Methode it's erased when i simpl click

[RemiDufloer]

Bug description
A clear and concise description of what the bug is.

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.

Clicking on a class or methods with a simple click. With the mouse goes over, without clicking, on other methods or class. You see this is delete. If you double click this come back.

The packages have almost the same behavior, it erases but I don't really know how this happens I feel like it's quite arbitrary
Edit : I think when you double click on a package and with the mouse goes over, without clicking, on other methods or class. You see this is erased

Expected behavior

normally packages, methods or classes are not supposed to stop showing up.

Screenshots

Version information:

• Pharo Version [e.g 10]