Thanks for the rapid response. It turns out that dragging individual managers to the graphics window and docking to the CENTER position groups them on a tabbed document. I had been dragging to the LEFT SIDE position, which just stacked one next to the other, keeping them separated. All good now. Thanks again.

I usually work with Toolpaths, Solids, Planes and Levels managers grouped together on a tabbed window, undocked from the graphics screen and on another monitor. Somehow though, the levels manager has gotten split off in a separate window and I can't remember how to get it back as a tab with the others. I can see how to switch managers from docked to floating, but not how to group them on a single window. This is in MC 2021. Any help is much appreciated.

Has anyone experienced their graphics screen going blank, including axis lines and gnomons? Statistics says that I still have all entities and operations that I should but they're not visible, and the x and y coordinates of the cursor display this: X: nan, Y:nan. Only one file is effected; others open and display fine.