When I use the zero-config debugger of PhpStorm it sometimes just hangs/freezes the page until I turn it off, after which it usually still breaks on the breakpoint. What could this be?
It sounds like you have more than one debug session (e.g. have one in debug mode right now and trying to debug another page/request while 1st one is still active).
If that's so -- either end current debug session first before making another request ... or increase the number of simultaneous sessions in PhpStorm settings. By defaults it is set to 1
.. so other sessions will wait till current one ends or PHP/web server terminates such stalled session. Make it 2
or maybe even 3
.
Settings/Preferences | Languages & Frameworks | PHP | Debug | Max. simultaneous sessions