From f98c14c2907e85f7fb11af08e8c43f9d99053dee Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Sat, 29 Feb 2020 12:10:20 +0100
Subject: [PATCH] tform: prevent MouseWatcherRegion leave event being fired
 twice

Fixes #858
---
 panda/src/tform/mouseWatcher.cxx | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/panda/src/tform/mouseWatcher.cxx b/panda/src/tform/mouseWatcher.cxx
index 9344d51d7d..74cb7692d3 100644
--- a/panda/src/tform/mouseWatcher.cxx
+++ b/panda/src/tform/mouseWatcher.cxx
@@ -726,6 +726,9 @@ clear_current_regions() {
       MouseWatcherRegion *old_region = (*old_ri);
       old_region->exit_region(param);
       throw_event_pattern(_leave_pattern, old_region, ButtonHandle::none());
+      if (_preferred_region == old_region) {
+        _preferred_region = nullptr;
+      }
       ++old_ri;
     }