Initial screen refresh closes control interface

[ZARE]

Hi, I created an app with a date picker controll and a button which invokes a flow. As a user starts the app using URL, the date picker control is instantly available for value-setting. However, there is an initial loading/refresh/initializing or what... i don't know, but it seems when a user profile loads (showing button for profile and Sign out button in upper right corner), control interface closes. This means if you started right away to choose tha date, you probably won't be quick enough to choose it and picker will be closed, you will need to open it again. I have nothing in OnStart nor OnVisible events on the screen, nothing I am loading.

This is not going to be easy accepted by end-users, any help is appreciated. If I could have control disabled until this loading is done it would be good enough.