diff --git a/regress/targets-panes.sh b/regress/targets-panes.sh
index 9ea936173..6ec5ffe7d 100644
--- a/regress/targets-panes.sh
+++ b/regress/targets-panes.sh
@@ -97,6 +97,10 @@ check "p:.{top-left}" "%0"
 check_ok select-pane -t p:0.%0
 check "p:0.+" "1" '#{pane_index}'	# next pane
 check "p:0.-" "3" '#{pane_index}'	# previous pane (wraps)
+check_fail "can't find pane: +0" "p:0.+0"
+check_fail "can't find pane: +foo" "p:0.+foo"
+check_fail "can't find pane: -0" "p:0.-0"
+check_fail "can't find pane: -foo" "p:0.-foo"
 
 # --- last pane (!) --------------------------------------------------------
 check_ok select-pane -t p:0.%2
diff --git a/regress/targets.sh b/regress/targets.sh
index 75ee3dbb8..768feda07 100644
--- a/regress/targets.sh
+++ b/regress/targets.sh
@@ -154,6 +154,13 @@ check "alpha:{previous}" "3"
 check "alpha:!" "2"		# last window
 check "alpha:{last}" "2"
 
+# Malformed relative offsets must fail rather than silently selecting the
+# current window.
+check_fail "can't find window: +0" "alpha:+0"
+check_fail "can't find window: +foo" "alpha:+foo"
+check_fail "can't find window: -0" "alpha:-0"
+check_fail "can't find window: -foo" "alpha:-foo"
+
 # --- combined and empty forms ---------------------------------------------
 #
 # Empty targets use the current pane from TMUX_PANE when there is no client.