Don't find document or assignements when right click on task

Hi everyone,

I have a task like that (sorry it's in french) :

I want to add a button in the right click menu only if the task contains a file.

I know how to add a button on right click and how to hide it when I want. But, I failed to know if the task have a file.

This is what I use actually:

// function called when creating right click menu
shellListing.Events.Register(Event_ShowContextMenu, function (selectedItems) {
    if(selectedItems.Count == 1 && selectedItems.ObjectVersions.Count == 1) { // check if there is a document, never true when right clic on task. That's my issue
	    var objVerSelected = selectedItems.ObjectVersions[0];
		var vault = shellFrame.ShellUI.Vault; // get vault
	    if(objVerSelected.HasAssignments && vault.ClassOperations.GetObjectClass(objVerSelected.Class).ObjectType == 10) { // check if it's a task
	        // I want to show it
	    } else {
	        // don't want to show it
	    }
    }
});

In my code, the task verfification (to check the Type object) work perfectly. The way to get file work when you right click on document but not when on a task link to document.

Also, `HasAssignments` is always false.

How can I do ?