fix: harden classroom presentations

config/plasma/xdg/kwinrc

@@ -82,15 +82,14 @@ NoiseStrength=2
 [org.kde.kdecoration2][$i]
 library=org.kde.breeze
 theme=Breeze
-# A pin and a close button, and nothing else.
-#
-# The pin is the Live View story: keeping a window above the others is a
-# window-manager state, not a feature the classroom has to invent. There is
-# deliberately no minimise button, because a minimised window is the one
-# thing a teacher cannot see the state of — measured, not assumed. Double
-# clicking the title bar still maximises, so nothing is unreachable.
+# A close button, and nothing else. `F` was the keep-above button, rendered
+# by Breeze as an unexplained double chevron beside Close. Classroom windows
+# that must stay above others request that state themselves; teachers do not
+# need a title-bar toggle for it. There is deliberately no minimise button,
+# because a minimised window is the one thing a teacher cannot see the state
+# of. Double clicking the title bar still maximises ordinary windows.
 ButtonsOnLeft=
-ButtonsOnRight=FX
+ButtonsOnRight=X
 ShowToolTips=false
 BorderSize=None
 BorderSizeAuto=false