Hi Fabio,
Thank you for the update.
We have checked reported issue by adding ComboBoxAdv inside the News tile. In mouse hover Combobox items background is set to Transparent, because, in this sample we have set MetroBrush as Transparent. Due to this the ComboBox item disappear in mouse over. We have confirmed that this is sample level issue and we suggest you to set the suitable color for “MetoBrush”.
We have modified the sample and set MetroBrush as Red. Please download the sample from the below location.
Sample:
Data_BindingRegards,
Priyanga B