$broswerRestrictFolders doesn't work if folder name contains a space

[TechnoSwiss]

var $browserRestrictFolders = array('/storage/Virtualbox VMs','/storage');

The first path in the configuration file will not show any sub-folders, the second path shows all sub-folders, including those under '/storage/Virtualbox VMs'. It appears the issue is only if the path contains a space, that RestrictFolder option doesn't work.

virtualbox 6.1, phpvirtualbox installed with https://github.com/phpvirtualbox/phpvirtualbox/tree/develop/packaging/install-scripts using the development option

Things I've tried to get around it (all result in same issue, inability to show sub-folders):
array('/storage/Virtualbox\ VMs')
array(''/storage/Virtualbox VMs'')
array('"/storage/Virtualbox VMs"')
array(''/storage/Virtualbox VMs'')
array('/storage/Virtualbox VMs')

symbolic link /tmp/VMs -> /storage/Virtualbox\ VMs
array('/tmp/VMs')