But this is my work computer which is subject to centrally administered group policies over which I have no control, maybe something in those is interfering?
Yepp, that would do it. Changing the shells settings is a privileged operation that may well be overridden by policy. You might want to just use the stand-alone version. You can still doube-click in the recent files list there, and do all operations from the main window and as long as you’re allowed to execute programs (which you obviously) are, it won’t be interfered with by such policies.