After the initial install there is an overlay that provides a description and progress of syncing. If a user clicks on the main UI buttons (Overview, Send, Receive, Transactions) while that overlay is visible, nothing seems to happen. The buttons respond as if clicked (background color changes) but other than that nothing seems to respond. if you look REALLY closely, you can see that actually the UI is responding and changing, but it's masked out behind the overlay screen.

Two suggestion, in my personal order of preference:

1. Clicking anywhere outside of the overlay just closes the overlay.
2. The overlay covers everything and you're essentially forced into clicking the 'Hide' button to reveal the UI behind it.

There's a short video of the behavior posted here:
https://twitter.com/statusquont/status/1278465322278948864