diff --git a/src/ex_cmds2.c b/src/ex_cmds2.c
index 3c73030..af7aa4b 100644
--- a/src/ex_cmds2.c
+++ b/src/ex_cmds2.c
@@ -1864,7 +1864,7 @@
     char_u	*p;
     int		old_arg_idx = curwin->w_arg_idx;
 
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return;
     if (argn < 0 || argn >= ARGCOUNT)
     {
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 438cb35..d2a6681 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -5454,7 +5454,7 @@
     static void
 ex_bunload(exarg_T *eap)
 {
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return;
     eap->errmsg = do_bufdel(
 	    eap->cmdidx == CMD_bdelete ? DOBUF_DEL
@@ -5470,7 +5470,7 @@
     static void
 ex_buffer(exarg_T *eap)
 {
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return;
     if (*eap->arg)
 	eap->errmsg = e_trailing;
@@ -6774,7 +6774,7 @@
 		       || eap->cmdidx == CMD_tabfind
 		       || eap->cmdidx == CMD_tabnew;
 
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return;
 
 #ifdef FEAT_GUI
@@ -6904,7 +6904,7 @@
 {
     int tab_number;
 
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return;
     switch (eap->cmdidx)
     {
@@ -7157,7 +7157,7 @@
     int		need_hide;
     int		exmode_was = exmode_active;
 
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return;
     /*
      * ":vi" command ends Ex mode.
diff --git a/src/macros.h b/src/macros.h
index 0f5ab77..d685dea 100644
--- a/src/macros.h
+++ b/src/macros.h
@@ -340,8 +340,9 @@
 /* Wether a command index indicates a user command. */
 #define IS_USER_CMDIDX(idx) ((int)(idx) < 0)
 
+// Give an error in curwin is a popup window and evaluate to TRUE.
 #ifdef FEAT_TEXT_PROP
-# define NOT_IN_POPUP_WINDOW not_in_popup_window()
+# define ERROR_IF_POPUP_WINDOW error_if_popup_window()
 #else
-# define NOT_IN_POPUP_WINDOW 0
+# define ERROR_IF_POPUP_WINDOW 0
 #endif
diff --git a/src/popupwin.c b/src/popupwin.c
index 99ef290..ea1a1e1 100644
--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -1336,7 +1336,7 @@
 }
 
     int
-not_in_popup_window()
+error_if_popup_window()
 {
     if (bt_popup(curwin->w_buffer))
     {
diff --git a/src/proto/popupwin.pro b/src/proto/popupwin.pro
index e026506..1eb2c10 100644
--- a/src/proto/popupwin.pro
+++ b/src/proto/popupwin.pro
@@ -21,7 +21,7 @@
 void f_popup_move(typval_T *argvars, typval_T *rettv);
 void f_popup_getpos(typval_T *argvars, typval_T *rettv);
 void f_popup_getoptions(typval_T *argvars, typval_T *rettv);
-int not_in_popup_window(void);
+int error_if_popup_window(void);
 void popup_reset_handled(void);
 win_T *find_next_popup(int lowest);
 int popup_do_filter(int c);
diff --git a/src/version.c b/src/version.c
index fcdf562..bf1a1f2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1555,
+/**/
     1554,
 /**/
     1553,
diff --git a/src/window.c b/src/window.c
index 4369129..ee616ee 100644
--- a/src/window.c
+++ b/src/window.c
@@ -87,7 +87,7 @@
 #endif
     char_u	cbuf[40];
 
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return;
 
 #ifdef FEAT_CMDWIN
@@ -735,7 +735,7 @@
     int
 win_split(int size, int flags)
 {
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return FAIL;
 
     /* When the ":tab" modifier was used open a new tab page instead. */
@@ -1523,7 +1523,7 @@
     win_T	*wp2;
     int		temp;
 
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return;
     if (ONE_WINDOW)	    // just one window
     {
@@ -2379,7 +2379,7 @@
     tabpage_T   *prev_curtab = curtab;
     frame_T	*win_frame = win->w_frame->fr_parent;
 
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return FAIL;
 
     if (last_window())
@@ -4240,7 +4240,7 @@
     win_T	*owp = curwin;
 #endif
 
-    if (NOT_IN_POPUP_WINDOW)
+    if (ERROR_IF_POPUP_WINDOW)
 	return;
     if (text_locked())
     {