patch 8.1.1580: cannot make part of a popup transparent
Problem: Cannot make part of a popup transparent.
Solution: Add the "mask" option.
diff --git a/src/structs.h b/src/structs.h
index 5787d2b..c664f0e 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -2916,6 +2916,7 @@
colnr_T w_popup_mincol; // close popup if cursor before this col
colnr_T w_popup_maxcol; // close popup if cursor after this col
int w_popup_drag; // allow moving the popup with the mouse
+ list_T *w_popup_mask; // list of lists for "mask"
# if defined(FEAT_TIMERS)
timer_T *w_popup_timer; // timer for closing popup window