diff --git a/src/structs.h b/src/structs.h
index 79681cc..9f63949 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -2881,6 +2881,8 @@
     int		w_maxwidth;	    // "maxwidth" for popup window
     int		w_wantline;	    // "line" for popup window
     int		w_wantcol;	    // "col" for popup window
+    varnumber_T	w_popup_last_changedtick; // b:changedtick when position was
+					  // computed
 # if defined(FEAT_TIMERS)
     timer_T	*w_popup_timer;	    // timer for closing popup window
 # endif