diff -r df9d869cd5fd -r 691ed9f41729 src/Pure/Tools/debugger.scala
--- a/src/Pure/Tools/debugger.scala	Fri Apr 22 10:31:38 2022 +0200
+++ b/src/Pure/Tools/debugger.scala	Fri Apr 22 16:47:13 2022 +0200
@@ -65,7 +65,7 @@
     def toggle_breakpoint(breakpoint: Long): (Boolean, State) = {
       val active_breakpoints1 =
         if (active_breakpoints(breakpoint)) active_breakpoints - breakpoint
-      else active_breakpoints + breakpoint
+        else active_breakpoints + breakpoint
       (active_breakpoints1(breakpoint), copy(active_breakpoints = active_breakpoints1))
     }