Blocking input changes behavior of I/O systems responsible for passing the node input data:
* A blocked node should NOT have input events called. It is illegal to call actionImpl. Input method
and device-specific handlers like hoverImpl and focusImpl usually won't be called either.
* If the input method has a node selection method like focus or hover, nodes that block input should be
excluded from selection. If a node starts blocking while already selected may continue to be selected.
Determine if the node can currently handle input.
Blocking input changes behavior of I/O systems responsible for passing the node input data:
* A blocked node should NOT have input events called. It is illegal to call actionImpl. Input method and device-specific handlers like hoverImpl and focusImpl usually won't be called either. * If the input method has a node selection method like focus or hover, nodes that block input should be excluded from selection. If a node starts blocking while already selected may continue to be selected.