alt+tab does not work occasionally

Bugzilla Migration
2021-01-16T14:32:28Z

## Submitted by dinar
Assigned to **Olivier Fourdan `@olivier`**

**[Link to original bug (#16243)](https://bugzilla.xfce.org/show_bug.cgi?id=16243)**
## Description
alt+tab does not switch windows occasionally.
Package: xfwm4
Version: 4.12.5-1

Version: 4.12.0