My Keyword List and histogram turned invisible

So I have no idea what caused this, but recently my keyword list decided to turn invisible. Within the library module the histogram is also empty and hitting "i" does not result in cycling through the information overlay.

The main issue for my workflow are the invisble keywords though. I say invisible, because they are technically still there. I can see them when I filter images in library (see image attached). At one point they briefly reappeared, only for them to vanish again, when I thought that was a good point in time to optimize my catalog. 

I tried opening an older backup, which brought them back for a while, but even that didn't last long. I tried rebuilding my library from that backup by adding my newer images, but eventually I had to restart LR and they were gone again. 

Does anyone have a similar issue, or an idea what might help? Any input is greatly appreciated.