In LinqPad 9.4, I've been toggling the "Enable Mica background with Light theme" checkbox, which (for me, at least) seems to also control whether or not the LinqPad Settings window uses "native" Windows titlebars and window-borders - and I've come to prefer native Windows titlebars because I much prefer my specific Active Titlebar color - and I'm certain I can definitely feel UI actions (like dragging the window around) feels slighly more sluggish when the LinqPad Mica option is enabled - but much snappier when it's off.

...but regardless of the Mica switch, the LinqPad 9.4 main window seems to always use the nonnative window titlebar and borders/shadows.

Screenshots and notes here: https://imgur.com/a/eWjZZ8D