updated for version 7.3.306
Problem:    When closing a window there is a chance that deleting a scrollbar
            triggers a GUI resize, which uses the window while it is not in a
            valid state.
Solution:   Set the buffer pointer to NULL to be able to detect the invalid
            situation.  Fix a few places that used the buffer pointer
            incorrectly.
diff --git a/src/term.c b/src/term.c
index 77387e0..7798480 100644
--- a/src/term.c
+++ b/src/term.c
@@ -3017,12 +3017,20 @@
     if (width < 0 || height < 0)    /* just checking... */
 	return;
 
-    if (State == HITRETURN || State == SETWSIZE) /* postpone the resizing */
+    if (State == HITRETURN || State == SETWSIZE)
     {
+	/* postpone the resizing */
 	State = SETWSIZE;
 	return;
     }
 
+    /* curwin->w_buffer can be NULL when we are closing a window and the
+     * buffer has already been closed and removing a scrollbar causes a resize
+     * event. Don't resize then, it will happen after entering another buffer.
+     */
+    if (curwin->w_buffer == NULL)
+	return;
+
     ++busy;
 
 #ifdef AMIGA