Maybe a one-time freak thing but if this happens to you too... here's how to recover.
Situation: you may notice the 3 dot menu with no dot solid (selected) all dots are hollow empty circles. This is illogical because clearly the default stuff is showing normally in that space so at least one dot should be solid. The problem is if you try swiping left or right to access other stuff, nothing happens - that area of the screen is frozen with that content showing and the other 2 dots' worth of stuff remain inaccessible. Swipe .. swipe .. swipe .. nothing. Dots don't change, all dots are hollow.
Those dots remain inaccessible, as in Reboot... didn't help. Reboot... again. No change. All dots hollow. Swipe is dead.
Here's what worked for me: Make a phone call. Hands free, voice command, call somebody you love, not Tesla. When you do this, the 4th dot appears and its solid and phone stuff is now occupying that space while in the call, as it should. When the call is done hang up and the 4th dot goes away, now back to 3 dots but now one them is solid and that stuff is showing correctly in the space, and ... yeah! swiping works again! You can access all menus again by swiping left or right.
This was all on software 2018.50.6 4ec03ed
In all fairness it has been extremely cold around here lately, and maybe that piece of software was just legitimately frozen.
Situation: you may notice the 3 dot menu with no dot solid (selected) all dots are hollow empty circles. This is illogical because clearly the default stuff is showing normally in that space so at least one dot should be solid. The problem is if you try swiping left or right to access other stuff, nothing happens - that area of the screen is frozen with that content showing and the other 2 dots' worth of stuff remain inaccessible. Swipe .. swipe .. swipe .. nothing. Dots don't change, all dots are hollow.
Those dots remain inaccessible, as in Reboot... didn't help. Reboot... again. No change. All dots hollow. Swipe is dead.
Here's what worked for me: Make a phone call. Hands free, voice command, call somebody you love, not Tesla. When you do this, the 4th dot appears and its solid and phone stuff is now occupying that space while in the call, as it should. When the call is done hang up and the 4th dot goes away, now back to 3 dots but now one them is solid and that stuff is showing correctly in the space, and ... yeah! swiping works again! You can access all menus again by swiping left or right.
This was all on software 2018.50.6 4ec03ed
In all fairness it has been extremely cold around here lately, and maybe that piece of software was just legitimately frozen.