Well, it's a known bug with a lot of potential triggers. Basically what happens is an out of date mod or a corrupt file causes the game to generate several new blank event popups every in game day or so, making it impossible to play. And when I turned on debug tooltips in the console, they said the popups were issued by the event "holocrisis.(ID number)" so I suspected it was something to do with this mod. I disabled the mod, and the problem stopped, confirming it.

Parker Posey's Mouth could you describe the exact problem to me, please?

Not positive, but I think this is causing me an empty pop-up bug. debugtips points to the event ID "holocrisis.__"