I use darktable for my post-processing, but recently the lighttable view has defaulted to having all the sidebars collapsed. Generally speaking, I usually want them all opened up, and it used to work that way. I can't find any setting that appears to address the view state of the lighttable -- only whether modules within a sidebar are opened singly or multiples. When I open an image in the darkroom all the sidebars are open.
I'm running Debian 9 (Stretch) and darktable 2.2.1