diff --git a/config.c b/config.c
index d46b5f8e..40a7e81b 100644
--- a/config.c
+++ b/config.c
@@ -1026,6 +1026,11 @@ parse_mouse_combos(struct config *conf, const char *combos, key_combo_list_t *ke
             *key = '\0';
             if (!parse_modifiers(conf, combo, key - combo, &modifiers, path, lineno))
                 goto err;
+            if (modifiers.shift) {
+                LOG_AND_NOTIFY_ERR("%s:%d: Shift cannot be used in mosue bindings",
+                                   path, lineno);
+                goto err;
+            }
             key++;  /* Skip past the '+' */
         }
 
diff --git a/doc/footrc.5.scd b/doc/footrc.5.scd
index 64f9c500..d5ea808d 100644
--- a/doc/footrc.5.scd
+++ b/doc/footrc.5.scd
@@ -369,6 +369,10 @@ of the modifiers *must* be valid XKB key names, and the button name
 *must* be a valid libinput name. You can find the button names using
 *libinput debug-events*.
 
+Note that *Shift* cannot be used as a modifier in mouse bindings since
+it is used to enable selection when the client application is grabbing
+the mouse.
+
 The trailing *COUNT* is optional and specifies the click count
 required to trigger the binding. The default if *COUNT* is omitted is
 _1_.