Right-click the Event structure border and select Lock Panel Until Handler Completes from the shortcut menu to lock the front panel when an event handled by that event case occurs. This menu option is enabled by default, but you can enable or disable the option for each event case. LabVIEW queues mouse clicks, key presses, and other user actions on that front panel until the event case completes, then processes pending events in the order received.
You cannot disable this option for filter events, because LabVIEW cannot finish processing a filter event until its case completes. Allowing LabVIEW to process other events while it is handling a filter event could cause events to occur out of order.
LabVIEW does not lock the front panel during a Timeout case, even if the same event case locks the user interface for other events it is configured to handle.