--- a/src/popupwin.c
+++ b/src/popupwin.c
@@ -601,8 +601,10 @@ popup_adjust_position(win_T *wp)
 	wp->w_topline = wp->w_buffer->b_ml.ml_line_count;
 
     // Compute width based on longest text line and the 'wrap' option.
+    // Use a minimum width of one, so that something shows when there is no
+    // text.
     // TODO: more accurate wrapping
-    wp->w_width = 0;
+    wp->w_width = 1;
     for (lnum = wp->w_topline; lnum <= wp->w_buffer->b_ml.ml_line_count; ++lnum)
     {
 	int len = vim_strsize(ml_get_buf(wp->w_buffer, lnum, FALSE));
@@ -704,6 +706,48 @@ typedef enum
 } create_type_T;
 
 /*
+ * Make "buf" empty and set the contents to "text".
+ * Used by popup_create() and popup_settext().
+ */
+    static void
+popup_set_buffer_text(buf_T *buf, typval_T text)
+{
+    int	    lnum;
+
+    // Clear the buffer, then replace the lines.
+    curbuf = buf;
+    for (lnum = buf->b_ml.ml_line_count; lnum > 0; --lnum)
+	ml_delete(lnum, FALSE);
+    curbuf = curwin->w_buffer;
+
+    // Add text to the buffer.
+    if (text.v_type == VAR_STRING)
+    {
+	// just a string
+	ml_append_buf(buf, 0, text.vval.v_string, (colnr_T)0, TRUE);
+    }
+    else
+    {
+	list_T *l = text.vval.v_list;
+
+	if (l->lv_len > 0)
+	{
+	    if (l->lv_first->li_tv.v_type == VAR_STRING)
+		// list of strings
+		add_popup_strings(buf, l);
+	    else
+		// list of dictionaries
+		add_popup_dicts(buf, l);
+	}
+    }
+
+    // delete the line that was in the empty buffer
+    curbuf = buf;
+    ml_delete(buf->b_ml.ml_line_count, FALSE);
+    curbuf = curwin->w_buffer;
+}
+
+/*
  * popup_create({text}, {options})
  * popup_atcursor({text}, {options})
  */
@@ -789,31 +833,7 @@ popup_create(typval_T *argvars, typval_T
 	// TODO: find tab page "nr"
 	emsg("Not implemented yet");
 
-    // Add text to the buffer.
-    if (argvars[0].v_type == VAR_STRING)
-    {
-	// just a string
-	ml_append_buf(buf, 0, argvars[0].vval.v_string, (colnr_T)0, TRUE);
-    }
-    else
-    {
-	list_T *l = argvars[0].vval.v_list;
-
-	if (l->lv_len > 0)
-	{
-	    if (l->lv_first->li_tv.v_type == VAR_STRING)
-		// list of strings
-		add_popup_strings(buf, l);
-	    else
-		// list of dictionaries
-		add_popup_dicts(buf, l);
-	}
-    }
-
-    // Delete the line of the empty buffer.
-    curbuf = buf;
-    ml_delete(buf->b_ml.ml_line_count, FALSE);
-    curbuf = curwin->w_buffer;
+    popup_set_buffer_text(buf, argvars[0]);
 
     if (type == TYPE_ATCURSOR)
     {
@@ -1112,6 +1132,22 @@ f_popup_show(typval_T *argvars, typval_T
     }
 }
 
+/*
+ * popup_settext({id}, {text})
+ */
+    void
+f_popup_settext(typval_T *argvars, typval_T *rettv UNUSED)
+{
+    int		id = (int)tv_get_number(&argvars[0]);
+    win_T	*wp = find_popup_win(id);
+
+    if (wp != NULL)
+    {
+	popup_set_buffer_text(wp->w_buffer, argvars[1]);
+	popup_adjust_position(wp);
+    }
+}
+
     static void
 popup_free(win_T *wp)
 {