diff --git a/regress/alerts.sh b/regress/alerts.sh
index cfb84c711..2b9e4f495 100644
--- a/regress/alerts.sh
+++ b/regress/alerts.sh
@@ -254,6 +254,19 @@ assert_unchanged @log ''
 $TMUX set -wut mon:w0 monitor-activity ||
 	fail "unset monitor-activity w0 failed"
 
+# Creating a non-current window counts as activity when monitor-activity is
+# enabled in the window defaults.
+$TMUX set -wg monitor-activity on || fail "set global monitor-activity failed"
+$TMUX set -g @log '' || fail "reset @log failed"
+$TMUX neww -d -t mon: -n newact cat || fail "new-window newact failed"
+wait_for @log '|alert-activity:mon:newact'
+wait_for_fmt mon:newact '#{window_activity_flag}' 1
+flags_have mon:newact '#'
+$TMUX set -wug monitor-activity ||
+	fail "unset global monitor-activity failed"
+$TMUX selectw -t mon:newact || fail "select-window newact failed"
+$TMUX selectw -t mon:w0 || fail "select-window w0 failed"
+
 # monitor-silence: a quiet window fires alert-silence after the interval
 # and sets the silence flag, shown as ~ in window_flags. The hook fires
 # only once while the flag remains set even though the timer keeps
@@ -273,6 +286,22 @@ wait_for_fmt mon:silw '#{window_silence_flag}' 0
 flags_lack mon:silw '~'
 $TMUX selectw -t mon:w0 || fail "select-window w0 failed"
 
+# Activity resets the silence timer: output before the original deadline
+# prevents an alert until a full quiet interval has passed afterwards.
+$TMUX neww -d -t mon: -n silreset cat || fail "new-window silreset failed"
+$TMUX set -g @log '' || fail "reset @log failed"
+$TMUX set -wt mon:silreset monitor-silence 2 ||
+	fail "set monitor-silence silreset failed"
+sleep 1
+activity mon:silreset
+assert_unchanged @log ''
+wait_for @log '|alert-silence:mon:silreset'
+wait_for_fmt mon:silreset '#{window_silence_flag}' 1
+$TMUX set -wt mon:silreset monitor-silence 0 ||
+	fail "reset monitor-silence silreset failed"
+$TMUX selectw -t mon:silreset || fail "select-window silreset failed"
+$TMUX selectw -t mon:w0 || fail "select-window w0 failed"
+
 # A window linked into two sessions: the hook fires once per winlink and
 # the flag is set in both sessions. Selecting the window in one session
 # clears the flags on every winlink.