Issue I560 [defect-gui,med-high] Fast adjust screen crash on GUI events when PA loading. Test quickly entering and exiting Fast Adjust screens, dozens of times in rapid succession. Holding down F key and then clicking Fast Adjust. More specifically, on main screen clicking Fast Adjust button and very shortly after pressing F key (before Fast Adjust screen opens). After entering Fast Adjust screen press ESC. This crashes it. Disabling asynchronous I/O ("simion.debug.allow_asynchronous_io=false" in 8.0.6-TEST10) stops this. Affects 8.0.6-TEST9 and probably certain earlier versions. Not yet resolved.