First, please download an install plugin version 220.127.116.11 installed, then try again. (It's the final plugin in the v3 series, not 18.104.22.168.) You can find it here: https://portal.nextlimit.com/
We recently assisted another user who might have been experiencing the same issue as you. In his case, Windows was displaying a pop up dialog on a second monitor behind formZ which could not be dismissed (except by disconnecting the second monitor), so formZ appeared frozen.
Even if you don't have two monitors attached, you might try the solution below, which corrected the issue for Pointer.
This is likely a Windows issue that has affected many users, not just those of formZ / Maxwell. In your case, having a second monitor attached appears to be making it impossible to click on the dialog that’s appearing behind the window (on the second monitor).
In the forum thread linked to below, you might try the steps outlined by user “BillGateFollower.” It seems that setting FOREGROUNDLOCKTIMEOUT to 0 has solved this issue for many users. (Write down the value it is set to currently, so you can revert if necessary.)