I'm detecting keystrokes within a function anycodings_flutter like FocusNode 's onKey callback. At this anycodings_flutter time. 2.1.4 Self-test Error Messages. At power-up, the VT510 terminal executes When the Num Lock state is active on an EPC keyboard, "Num Lock" is displayed. Upon me using SendKeys to copy data from an Excel application to another (non-Microsoft) application, my Num Lock becomes disabled. Sub Test().