Custom Action Menu Items are not always shown

Hello!

My question concerns the action menu items on the case edit page. I'm trying to add a custom action item that is only shown when some specific requirements are fulfilled. At the moment I basically use the following code:

		attributes: {
            "UsrIsMatchingTicket" : {
                "dataValueType": Terrasoft.DataValueType.BOOLEAN,
                "value": false
            }
        },
.....
		methods: {
            onEntityInitialized: function() {
                this.callParent(arguments);
                var esq = Ext.create("Terrasoft.EntitySchemaQuery", .....) // some longer query that in the end sets the attribute "UsrIsMatchingTicket" to true or false, depending on the query
            },
            getActions: function() {
				var actionMenuItems = this.callParent(arguments);
				actionMenuItems.addItem(this.getButtonMenuItem({
					"Tag": "doSomething",
                    "Caption": "Do Something",
                    "Visible": {bindTo: "UsrIsMatchingTicket"},
				}));
				return actionMenuItems;
			},
        }

This code works only, when I've opened the case and then reload. However, when I'm in the cases section and then click on a specific case, the action item is never shown, even when the attribute "UsrIsMatchingTicket" is set to true. Where is the problem in this code?