I ran into something really similar after upgrading Emacs—my ediff setup suddenly felt broken, and I couldn't figure out why the control window was missing. Turned out it was some theme or face setting that didn’t play well with the new frame behavior in Emacs 29. Digging into set-face-attribute calls and checking what lsp-ui was doing helped me fix it eventually. Funny enough, during one of my many debugging breaks, I stumbled across this weird little game called crazy cattle 3d. It’s basically sheep bumping into each other in glorious chaos. Totally random, but weirdly relaxing after wrestling with Emacs config for hours.