The button name doesn't change when you click it. I also added a log inside the handler, that code is not running at all. So it is not that it tries to change the button text but fails, the on click code just isn't running.
Updated to dev-master and now it works. Seems this could use a release, unless you'r thinking other stuff is broken on master that is not in the last release.
OS: Windows 10 (10.0.18363 Build 18363) php: 7.4.6 x64 thread safe php-gui: v0.1.1
The button name doesn't change when you click it. I also added a log inside the handler, that code is not running at all. So it is not that it tries to change the button text but fails, the on click code just isn't running.